T E C H N I C A L R E P O R T 0 9 8

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1 T E C H N I C A L R E P O R T 9 8 The Effects of Planting Density on the Growth and Yield of Lodgepole Pine, Interior Spruce, Interior Douglas-fir, and Western Larch: 16- to 26-year Results from EP

2 The Effects of Planting Density on the Growth and Yield of Lodgepole Pine, Interior Spruce, Interior Douglas-fir, and Western Larch: 16- to 26-year Results from EP964 Louise de Montigny, Suborna Ahmed, and Valerie LeMay The Best Place on Earth

3 The use of trade, firm, or corporation names in this publication is for the information and convenience of the reader. Such use does not constitute an official endorsement or approval by the Government of British Columbia of any product or service to the exclusion of any others that may also be suitable. Contents of this report are presented for discussion purposes only. Funding assistance does not imply endorsement of any statements or information contained herein by the Government of British Columbia. Uniform Resource Locators (urls), addresses, and contact information contained in this document are current at the time of printing unless otherwise noted. Print edition: isbn Electronic/PDF edition: ISBN Citation de Montigny, L., S. Ahmed, and V. LeMay The effects of planting density on the growth and yield of lodgepole pine, interior spruce, interior Douglas-fir, and western larch: 16- to 26-year results from ep964. Prov. B.C., Victoria, B.C. Tech. Rep. TR98. Prepared by Louise de Montigny British Columbia Ministry of Forests, Lands and Natural Resource Operations Resource Practices Branch Victoria, B.C. Suborna Ahmed University of British Columbia Vancouver, B.C. Valerie LeMay University of British Columbia Vancouver, B.C. Copies of this report may be obtained from: Crown Publications, Queen s Printer PO Box 9452 Stn Prov Govt Victoria, BC v8w 9v For information on other publications in this series, visit Province of British Columbia When using information from this report, please cite fully and correctly.

4 ABSTRACT Long-term monitoring of planting density trials provides critical information about the effects of planting density on the growth, development, and yield of conifer plantations. Experimental Project 964 (EP964), which was established in the Interior of British Columbia by the B.C. Ministry of Forests between 1985 and 2, comprises 26 standardized planting density installations distributed over nine forest districts and four biogeoclimatic zones. The installations include four commercial conifer species laid out using five planting density treatments. The installations with this Experimental Project have now been monitored for about years since planting. In this project, we analyzed data for 17 EP964 installations planted with interior lodgepole pine, interior Douglas-fir, interior spruce, and western larch. We focussed our analyses to answer three questions of interest to forest managers that concern: (1) the consistency of planting density effects on the growth and yield for particular tree species; (2) the optimal planting density to achieve the highest timber value per area for particular timber products; and (3) the forest health effects of planting density on pine mortality. Over the four species planted, statistically significant differences were noted in tree size, yield, and growth variables, particularly between extreme planting densities. These differences appear to increase with time after planting. Most variables show a trend over time that regularly increases (e.g., volume per hectare) with density, or regularly decreases with density (e.g., dbh); however, height and height increments were generally not affected. This may change with time as competition-based mortality increases, in turn leading to an increase in the structural diversity of plantations. For timber products such as lumber that require larger trees with less taper (e.g., lumber) as well as high yield, the analysis of EP 964 results supports the use of midrange planting densities. For timber products based on biomass, including biofuels and carbon credits, the higher densities provide higher volume per hectare and therefore higher aboveground biomass per hectare, but planting at the extreme density may not be economically justified. The number of lodgepole pine recorded as dead also increased over time but did not appear to differ among planting densities. ACKNOWLEDGEMENTS Wayne Johnstone, Emeritus Scientist, is gratefully acknowledged for having the foresight to establish these valuable experiments, and for participating in discussions at the field sites we visited. Thank you to B.C. Ministry of Forests, Lands and Natural Resource Operations (MFLNRO) staff Dave Goldie for ongoing field measurements and database assistance, and reviewers Harry Kope, Kevin Astridge, and Peter Ott for technical reviews and valuable feedback. Thanks to Paul Nystedt of the Ministry of Environment and Susan Bannerman of Kaatza Publishing Services for assistance with the production of this report. Funding for this project came from the MFLNRO Research Program. iii

5 CONTENTS Abstract Acknowledgements Introduction Materials and Methods Experimental Design and Measurements Data Compilation for Each Installation Analyses by Installation Interpreting Results and Addressing Management Questions Installation Data Summaries Results and Discussion Effects of Planting Density on Tree Size and Yield Trade-offs between Tree Size and Yield Damage Agents and Pine Mortality Summary Literature Cited Appendix 1 EP964 Installation Data Summaries tables 1 Species planted and locations of the Experimental Project 964 installations analyzed in this report Differences in mean dbh and volume per hectare Differences in mean dbh MAI and volume per hectare MAI figures 1 Locations of Experimental Project 964 trials in British Columbia Mean dbh and volume per hectare over time for installation with five planting densities iii iii iv

6 1 INTRODUCTION Long-term monitoring of planting density trials contributes critical information about the effects of planting density on the growth, development, and yield of conifer plantations. This monitoring also provides early growth data that are often lacking when calibrating the growth and yield models used to forecast future timber supply for both planted and natural stands. Using this information, decision makers can more confidently respond to forest management questions that require knowledge of: the consistency of planting density treatment effects on the growth and yield for particular tree species; the optimal planting density to achieve the highest timber value per area for particular timber products; and the effects of planting density on tree mortality from disease, insect, or other damage agents. Experimental Project 964 (EP964), which was established in the Interior of British Columbia by the B.C. Ministry of Forests from 1985 to 2, can offer many insights into these management questions. This project comprises 26 standardized planting density installations distributed over nine forest districts and four biogeoclimatic zones (see Figure 1). The installations include four commercial conifer species laid out using five planting density treatments (i.e., 5, 1, 15, 2, or 25 stems per hectare). These trials have now been monitored for about years since planting. Johnstone (21, 23, 24a, 24b, 26) reported earlier results for some of these installations. Generally, he noted that mean height was not affected by density, whereas mean diameter at breast height (dbh; diameter outside bark at 1.3 m above ground), volume per hectare, and periodic increments varied with density. He found a high rate of survival and did not detect any mortality differences among planting densities. Since early mortality of seedlings resulted in seedling replacement for up to 5 years following planting, mortality rates did not include early mortality owing to planting shock or excessive browsing or damage of seedlings by animals. In 211, Johnstone and van Thienen reported 2-year results for a single lodgepole pine installation (i.e., EP964.6). All mean tree-size variables (e.g., mean dbh over all trees in a plot) and yield variables (e.g., volume per hectare summed for all trees in a plot) differed among treatments, except for mean height and mean periodic height growth. They also noted that survival was very high and did not vary with planting density. Using the full set of repeated measures, graphs over years since planting indicated that mean dbh differences among plantation densities were increasing for this installation, whereas mean heights were similar, causing increasing differences in tree taper (i.e., indicated by height/dbh). As expected, wider spacing resulted in larger mean dbh values and greater taper; however, the volume per hectare at 2 years overlapped for upper planting densities, indicating that the production capacity had been reached. 1

7 FIGURE 1 Locations of Experimental Project 964 installations in British Columbia (B.C. Ministry of Forests and Range 27). In this report, we repeated these earlier analyses for 17 EP964 installations and incorporated recent additional measurements. These installations included: interior lodgepole pine (eight installations; Pinus contorta var. latifolia Dougl.); interior Douglas-fir (three installations; Pseudotsuga menziesii var. glauca [Mirb.] Franco); hybrid and Engelmann spruce (five installations; pure species or hybrids of Picea glauca (Moench) Voss and Picea engelmanii Parry); and western larch (one installation; Larix occidentalis Nutt.) (see Table 1). Because the Experimental Project 964 installations are now older, they are particularly well suited to provide forest managers with the information they need to address several issues of interest. We focussed our analysis to answer the following management questions. 2

8 1. For a given species, are the effects of planting density on size and yield consistent across sites? 2. Which planting density balances the trade-off between tree size and volume per hectare, resulting in the highest timber value per hectare? 3. Can the choice of planting density lower the risk of disease and (or) insect attack, and thus tree mortality? We first compiled the data for each installation to the plot level. We graphed the results for several variables by planting density over time, including mean tree size (e.g., mean dbh), yield (e.g., total volume per hectare), and growth (e.g., total volume per hectare mean annual increment). We then tested for differences in all these variables among the planting densities for each installation using the final measurement, which was obtained in 213 for most of the installations. TABLE 1 Species planted and locations of the Experimental Project 964 installations analyzed in this report Installation Biogeoclimatic Year estab- Last year Years since no. District Species subzone/variant lished Latitude Longitude measured planting 2 Nadina lodgepole pine SBSmc ' ' Skeena hybrid spruce SBSmc ' ' Stikine 5 Skeena lodgepole pine SBSdk ' ' Stikine 6 Nadina lodgepole pine SBSmc ' ' Central lodgepole pine SBSdw ' ' Cariboo 8 Kamloops Douglas-fir ICHmw ' ' Rocky lodgepole pine MSdk ' 115 3' Mountain 11 Rocky Mountain lodgepole pine MSdk ' ' Okanagan Shuswap 13 Central Cariboo Engelmann ICHmw ' 119 1' spruce hybrid spruce ICHmk ' ' Vanderhoof lodgepole pine SBSmc ' 124 2' Vanderhoof hybrid spruce ESSFmv ' 124 4' Headwaters Douglas-fir ICHmw ' ' Okanagan lodgepole pine ESSFxc ' ' Shuswap 23 Arrow hybrid spruce MSdm ' ' Boundary 24 Okanagan Douglas-fir ICHmw ' ' Shuswap 25 Okanagan Shuswap western larch ICHmw ' '

9 Using our analysis results, we prepared an overview of planting density effects by looking for logical consistencies across installations for a given planted species. To address the management question regarding the trade-off between tree size and volume per hectare, we prepared and interpreted an overlay of volume per hectare and mean dbh. To evaluate whether planting density might affect lodgepole pine tree mortality through disease or insect attack, we analyzed mortality effects by damage agent and by density over time. A meta-analysis for rust proportions in pine stands was also completed and reported separately (see LeMay and Ahmed 215). 2 MATERIALS AND METHODS 2.1 Experimental Design and Measurements The design of installations for Experimental Project 964 generally followed protocols described in Coates (1983), with minor variations (Johnstone 21). This resulted in a randomized complete block design (three blocks) for most installations. Installation (lodgepole pine) used a completely randomized design with three replicates, and installation (mixed pine and hybrid spruce, not analyzed) used a completely randomized design with two replicates. With a few exceptions (i.e., and ), 144 trees were planted in a arrangement in each experimental plot with regular spacing between trees to achieve the target plantation density. For 5 years after planting, seedlings that died from planting shock or animal browse were replaced with seedlings of the same age and seedlot from an on-site reserve plantation and ingrowth trees were removed. 1 At each measurement, species was recorded for all trees along with tree status (live versus dead), and dbh was measured. Some trees were measured for height at each measurement. For some measurements, crown width and height to live crown were measured on certain trees. Finally, for most measurements, damage (e.g., fork, dead top) and (or) damage agents (e.g., insects or diseases) were recorded for each tree. Although all trees were measured at each measurement period, the outer two boundary trees around the plot edge were not used in analyses; therefore, 64 trees (i.e., 8 8 trees) were analyzed for most installation plots. For a few plots within two installations (964.8 and ), some rows were missing (i.e., instead of 12 12), and because the outer two boundary trees around the edge were not used, this meant that 56 trees (i.e., the central 7 8 trees) were used in the analyses. Installation had a 1 1 configuration of trees, but the inner 8 8 trees were used in the analyses, which meant only one buffer tree row occurred around the plot edge. As noted, two installations were excluded from our analyses. Installation had mixtures of pine and spruce, as well as a different experimental design than the other installations, thus requiring another type of analysis. Installation had only two measurements. 1 Johnstone (21, 23, 24a, 24b, 26) indicated that tending continued to at least 1 years after planting. 4

10 2.2 Data Compilation for Each Installation Data for each installation were compiled by plot and measurement using the following steps. Data were checked for measurement or recording issues, such as: negative dbh or height increments; excessive mortality of any plot because of a site effect, rather than the planting density; unexpected species; and unexpected measures. Missing heights were imputed by fitting a Chapman-Richard s model of height from dbh using all installation trees with measured height and dbh. Missing dbh values were imputed by reversing the fitted model. Total volume and merchantable volume (.3 m stump height to a 1 cm top diameter inside bark) were obtained by integrating taper functions (fitted by Tony Kozak, Professor Emeritus, University of British Columbia, for Ministry of Forests, Lands and Natural Resource Operations) with dbh and height measures (or estimates) and modifying SAS code provided by the Ministry of Forests, Lands and Natural Resource Operations Forest Analysis and Inventory Branch. Plot trees were summarized to obtain tree-size variables (i.e., mean values over all trees) for each plot at each measurement, along with yield variables (i.e., summed over all trees in the plot). Mean annual increments were obtained by dividing the summarized variables by the years since planting (e.g., dbh mean annual increment = mean dbh of the plot years since planting). These values were then used to analyze the differences among plantation densities at the final measurement. The 12 variables included in the analysis for each installation were: (1) total volume per hectare; (2) total volume per hectare mean annual increment (MAI); (3) basal area per hectare; (4) basal area per hectare MAI; (5) mean dbh; (6) mean dbh MAI; (7) mean height; (8) mean height MAI; (9) mean volume per tree; (1) mean basal area per tree; (11) mean basal area per tree MAI; and (12) mean dbh over height (i.e., tree taper). For each variable, mean values were calculated for each treatment at each measurement time by averaging the three blocks for all installations, except for EP 964.7, where the three replicates of the completely randomized design were averaged. These averages were then used to graph the changes in tree size, yield, and growth over time. 2.3 Analyses by Installation Using the final measurement taken in 213 (for most installations), we employed two models to test treatment differences (i.e., plantation densities) for each variable. For installations laid out using a randomized complete block design, a mixed-effects model was used to test blocks as random effects and treatments as fixed effects (SAS 9.3, PROC MIXED). 2 For the installation laid out using a completely randomized design (964.7), a general linear model was used to test only fixed-effects treatments (SAS PROC 9.3, MIXED or GLM). If differences were detected for a variable (α =.5), then pairs of means t-tests were conducted for each pair of plantation densities, using a Bonferroni correction and LSMEANS to determine which densities differed. For each 2 All data analyses for this report were generated using SAS/STAT software, Version 9.3 of the SAS System for Windows Copyright SAS Institute Inc. SAS and all other SAS Institute Inc. product or service names are registered trademarks or trademarks of SAS Institute Inc., Cary, NC, USA. 5

11 installation, graphs of the repeated measures over time of each tree size, yield, or growth variable were obtained using the freeware R (version 3.2) and the plot( ) function. 2.4 Interpreting Results and Addressing Management Questions To focus our analysis on the three forest management questions of interest, we used the following procedures to interpret our results and conduct additional analyses. To determine the degree of consistency across all installations by species, we tested for differences among planting densities at the final measurement. To further assess differences among planting densities and how these changed over time, we examined graphs of each of the variables over time by density. To interpret the trade-off between tree size and yield (specifically, dbh and volume per hectare), we used information for installation 964.6, overlaying a graph that showed volume per hectare over time by planting density with a graph of dbh over time by planting density. To determine whether density treatments affected tree mortality, we tabulated the number of dead trees by planting density for all lodgepole pine installations. 2.5 Installation Data Summaries To enable comparisons, we prepared data summaries for each EP964 installation. Appendix 1 contains 17, two-page synopses that consolidate pertinent installation information and graphs of selected analysis results. The first page presents general installation location details, comprising: a general location map for the installation; a table of installation data, including: biogeoclimatic subzone/variant, geographic location, tenure, year established, years since planting, and year of last measurement; and a plot layout diagram, showing relative location of the treatment blocks within the installation along with details about the opening numbers and experimental design. At the bottom of the first page, a table presents the least squares means and differences in response to density treatments years after planting for the 12 variables included in the analysis. For the eight lodgepole pine installations, a table shows the results of the tree mortality by treatment analysis. The second page presents three sets of graphs that compare: tree-size variables (e.g., mean dbh, mean height, mean annual volume increment, and mean crown ratio) versus years after planting by treatment; yield variables (e.g., total volume and basal area per hectare) versus years after planting by treatment; and proportion of trees by dbh class and treatment, years after planting. 6

12 3 RESULTS AND DISCUSSION 3.1 Effects of Planting Density on Tree Size and Yield For all installations, we applied either a mixed-effects model or a general linear model to assess differences among treatments. If differences in a particular variable were detected, then pairwise comparisons were conducted to detect which plantation densities differed. In a few installations, particularly those containing spruce, some trees may have been too small at final remeasurement to detect differences. The first page of each installation summary in Appendix 1 provides a detailed table of least squares means and differences in response to density treatments years after planting. Table 2 shows a summary of results for mean dbh and volume per hectare, whereas Table 3 shows a similar summary for dbh MAI and volume per hectare MAI. In both tables, installations are grouped by species planted. In general, the 5 stems per hectare treatment differed from 25, but few differences were found between the 2 and 25 stem density treatments for these variables. Overall, almost all installations showed no differences in mean heights (except installations and ) or in height mean annual increments (except and 964.7) with differing density treatments. Excluding height variables, the following differences among treatments were observed at final measurement. For the three Douglas-fir installations (964.8, , ), variables were similar for the 15, 2, and 25 stems per hectare treatments, except for tree taper, which differed for two of the three installations. The 5 and 1 stem densities did not differ. In some cases, the 5 stems per hectare treatment also did not differ from the 15. For the single western larch installation (964.25), variables were also similar for the 15, 2, and 25 stem densities; however, unlike Douglas-fir, several variables differed between the 5, 1, and 15 stems per hectare treatments, including volume per hectare, basal area per hectare, and tree taper. For the eight lodgepole pine installations: showed differences in most pairs of densities for volume per hectare and basal area per hectare (as well as the mean annual increments), and for tree taper and showed no differences for tree taper at the 15, 2, and 25 stem densities showed differences for several variables but not for adjacent densities (e.g., 5 and 1 stem densities had similar results) showed differences for every pair of planting densities for most other variables. In contrast, and indicated only a few differences among pairs of densities and for only a few variables, notably taper and volume per hectare and basal area per hectare mean annual increment. 7

13 TABLE 2 Differences in mean dbh and volume per hectare. Planting densities with the same letter are not different (α =.5). Diameter at breast height Volume per hectare Installation Years since Planting density Planting density no. District Species planting Kamloops Douglas-fir 26 a ab bc c c a ab b ba* ba* Headwaters Douglas-fir 21 a a a** a a a ab bc c c Okanagan Shuswap Douglas-fir 17 a ab abc bc c a a a** a a Okanagan Shuswap western larch 16 a ab abc c c a b b b b Nadina lodgepole pine 24 a ab abc c c a b b b b Skeena Stikine lodgepole pine 24 a b bc cd d a ab bc bc c Nadina lodgepole pine 24 a b bc cd d a ab b b b Central Cariboo lodgepole pine 26 a b b b b a b bc cd d Rocky Mountain lodgepole pine 26 No differences were detected among treatments No differences were detected among treatments Rocky Mountain lodgepole pine 24 a b c cd d a ab abc c c Vanderhoof lodgepole pine 19 a ab ab ab b a a a** a a Okanagan Shuswap lodgepole pine 2 a b bc bc c a b c cd d Skeena Stikine Engelmann spruce 25 a b bc bc c a a a** a a Okanagan Shuswap hybrid spruce 24 No differences were detected among treatments a ab ab ab b Central Cariboo hybrid spruce 24 a b b b b No differences were detected among treatments Vanderhoof hybrid spruce 22 a ab ab b ba* a ab ab ab b Arrow Boundary hybrid spruce 18 No differences were detected among treatments a ab ab b ba* * Some switching of differences occurs (e.g., Installation 15: mean dbh for 5 stems per hectare differs from 2, but not from 25 stems per hectare). ** Overall differences were detected, but no pair of treatments differed. 8

14 TABLE 3 Differences in mean dbh MAI and volume per hectare MAI. Planting densities with the same letter are not different (α=.5). Diameter at breast height (mean annual increment) Volume per hectare (mean annual increment) Installation Years since Planting density Planting density no. District Species planting Kamloops lodgepole pine 26 a ab bc c c a ab b ba* ba* Headwaters Douglas-fir 21 a a a** a a a a b b b Okanagan Shuswap Douglas-fir 17 a ab ab ab b a ab b b b Okanagan Shuswap western larch 16 a ab abc c c a b b b b Nadina lodgepole pine 24 a ab bc c c a b b b b Skeena Stikine lodgepole pine 24 a b bc cd d a b bc bc c Nadina lodgepole pine 24 a b bc cd d a ab bc c bc Central Cariboo lodgepole pine 26 a b b b b a ab bc c d Rocky Mountain lodgepole pine 26 No differences were detected among treatments a ab ab ab b Rocky Mountain lodgepole pine 24 a b b c c a b b c c Vanderhoof lodgepole pine 19 a a a** a a a ab ab b b Okanagan Shuswap lodgepole pine 2 a b b bc c a b c c c Skeena Stikine Engelmann spruce 25 a b bc c c a ab ab b b Okanagan Shuswap hybrid spruce 24 No differences were detected among treatments a ab ab ab b Central Cariboo hybrid spruce 24 a b ab b b No differences were detected among treatments Vanderhoof hybrid spruce 22 a ab ab b ba* a ab ab b b Arrow Boundary hybrid spruce 18 No differences were detected among treatments a a a** a a * Some switching of differences occurs. ** Overall differences were detected, but no pair of treatments differed. 9

15 For the five spruce installations (964.4, , , , ), the 5 and 25 stems per hectare treatments showed differences but for tree-size variables at some locations and for yield variables at other locations. In particular: and (Engelmann spruce and hybrid spruce, respectively) indicated no differences for dbh and dbh mean annual increment but showed differences in volume and volume mean annual increment, whereas the reverse was the case for (hybrid spruce) (see Tables 2 and 3) (hybrid spruce) showed differences in tree-size variables (e.g., dbh, height, tree taper), with most differences detected for the 5 versus the 25 stem densities and, in some cases, the 1 versus the others. No differences were detected among the 15, 2, and 25 stems per hectare treatments. Similar results were obtained for Conversely, tree-size variables did not differ for EP , except for tree taper; however, volume per hectare differed for the 5 versus 25 stem densities, and basal area per hectare differed for the 5 versus 2 and 25 treatments. Similar results were obtained for volume per hectare and basal area per hectare mean annual increments. Again, no differences were detected among the 1, 2, and 25 stems per hectare treatments and showed very few differences and only for the 5 versus 25 stem densities. General trends regarding differences between the lowest and highest planting densities were detected for all installations. However, for other planting densities, variation with respect to which variables showed differences occurred even within species. The second page of each installation summary in Appendix 1 contains graphs for several of the 12 variables of interest by treatment over time. Generally, the 5 and 25 stems per hectare treatments showed the largest differences and these differences increase with time. Height was commonly little affected, but this may change as mortality causes changes in competition within plots that, in turn, will increase the structural diversity of the plantations. Although most variables showed a trend over time that consistently increases (e.g., volume per hectare) with density or consistently decreases with density (e.g., dbh), some cross-over occurred. For example, at installation 964.2, the tree-size variables dbh and volume per tree and their mean annual increments showed a switch between the 1 and 5 stems per hectare treatments, whereby the 1 stem density showed the largest values early on, but then the 5 stem density showed equal or larger values at 24 years after planting. 3.2 Trade-offs between Tree Size and Yield When we examined the trade-off between tree size and yield, it was apparent that larger trees are produced at lower planting densities, but higher yields resulted for higher planting densities. Using the lodgepole pine installation to illustrate this trade-off, Figure 2 shows similar volume per hectare values (~ 15 m 3 /ha at 24 years after planting) for the 15, 2, and 25 stems per hectare treatments; however, the 15 stem density showed a larger dbh (~ 15 cm), as might be expected. The 1 stems per hectare treatment 1

16 FIGURE 2 Mean dbh (black) and volume per hectare (grey) over time for installation with five planting densities: 5 (o), 1 ( ), 15 (+), 2 ( ), and 25 ( ) stems per hectare. had a dbh similar to the 15 treatment but with approximately 25 m 3 /ha less volume. Although the trees planted at this installation are not of rotation age, these differences indicate the importance of value estimation in plantations. Given that many timber products (notably lumber) require larger trees with less tree taper as well as a high yield, the EP964 planting density experiment appear to support the use of mid-range densities. For timber products requiring biomass, the upper planting densities provide higher volume per hectare and therefore higher aboveground biomass per hectare, since most of this is held in the main stem, particularly for conifers with smaller branches. Because the results for the 2 and 25 stems per hectare treatments seem very similar, the cost of the 5 additional seedlings per hectare may not be justified. This would also be the case from a carbon sequestration or carbon credit perspective. Nevertheless, these observations are very preliminary. Further analyses of these installations are required, with a particular emphasis on differences among species and across locations. 3.3 Damage Agents and Pine Mortality For each of the eight lodgepole pine plantations, the numbers of trees by damage agent and the numbers of dead trees were tallied over all plots with the same planting density for each measurement. As expected, the numbers of trees with some type of damage recorded increased over time. A number of forks, crooks, multiple stems, and multiple tops were recorded for all pine installations, and all had some degree of rusts and/or cankers. Mountain pine beetle was only recorded at and 964.7; had elytroderma needlecast on several trees along with Warren s root collar weevil, and a num- 11

17 ber of stems listed in poor condition. Lodgepole pine terminal weevil was recorded for several trees in the last measurement for EP Over all eight installations, no differences were noted over the five planting densities, with the possible exception of installation , in which more forks were recorded for wider spacings (i.e., lower planting densities). Similarly, the number of trees recorded as dead increased over time for these pine installations. Again, there was little evidence that this differed among planting densities. Also, the numbers of trees recorded as dead increased over time, but this did not appear to differ by planting density; however, as the trees grow in size, competition-based mortality will begin to occur and will likely be higher at the higher planting densities. 4 SUMMARY Over the four species planted, differences were noted in size (e.g., dbh), yield (e.g., volume per hectare), and growth (e.g., dbh mean annual increment) variables, particularly between extreme densities; as expected, these differences increased with time after planting. In general, height was not affected, except for a few installations and for the two extreme densities at those locations; however, this may change with time as competition-based mortality increases that, in turn, will increase the structural diversity of the plantations. In some installations, few differences were detected, likely because the trees are still too small. This appears to be the case for some spruce sites but may apply to two of the lodgepole pine installations. For variables showing differences, the trend over time regularly increases (e.g., volume per hectare) or regularly decreases (e.g., dbh) with planting density; however, some crossover of densities was noted. For Douglas-fir, most size, yield, and growth variables were generally similar for the 15, 2, and 25 stems per hectare treatments, except for tree taper, which differed for two of the three installations. The 5 and 1 stems per hectare treatments did not differ. Results for the single larch installation were similar to those for Douglas-fir except that several tree size and yield variables differed between the 5, 1, and 15 stems per hectare treatments, including volume per hectare, basal area per hectare, and tree taper. The eight lodgepole pine installations included in our analysis also showed inconsistent results. Results were also more varied for the spruce installations, where tree size variables differed in some installations and yield variables differed in other installations. Many timber products require larger trees with less taper (e.g., lumber) along with high yield. Our analyses of Experimental Project 964 appear to support the use of mid-range densities. For other timber products requiring biomass, such as biofuels and carbon credits, the higher planting densities provide higher yield; however, the 2 and 25 stem per hectare densities seem to provide similar yields. These are preliminary observations; further analyses of these installations are required, particularly to detect differences among species and across locations. Common damage observed in the lodgepole pine installations included broken tops, crooks, multiple stems, and forks. Animal browsing and me- 12

18 chanical damage are likely causes of much of this damage but weevils and other damage agents were also noted. No differences in damage were noted with differing densities. An in-depth examination of all damage agents over time would provide a more comprehensive view of plantation health. The number of trees recorded as dead also increased over time but did not appear to differ among planting densities. Nevertheless, competition-based mortality is expected to increase in the higher planting densities. Continued monitoring of the installations within Experimental Project 964 is strongly recommended. This information will greatly enhance our knowledge of planted forests, resulting in improved decision making. 13

19 APPENDIX 1 EP964 Installation Data Summaries EP964.2 Data summary for Installation 2 (Nadina District; lodgepole pine) Plot layout EP964 Installation 2 McBride Lake Nadina Forest District Opening numbers: 93L.4.3 and 39 Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) Installation data BEC unit SBSmc2 Location McBride Lake Latitude 54 3' Longitude ' TSA/TFL Morice Year established 1988 Years since planting 24 Last measured m Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: Tree mortality by treatment Planting density Years after planting Least squares means and differences in response to density treatments, 24 years after planting a Planting density Variable Total volume per hectare a b b b b Basal area per hectare a b bc bc d Mean dbh a ab abc c c Mean height Mean volume per tree.17 a.178 ab.7812 abc.546 c.594 c Mean basal area per tree.2577 a.2375 ab.1774 abc.1364 c.141 c Mean dbh over height a b c 1.54 c c Mean Annual Increment Volume per hectare a b b b b Basal area per hectare.5249 a.9846 ab bc bc c Mean dbh.7387 a.7193 ab.6186 abc.5419 c.5515 c Mean height.3769 a.4217 ab.3995 ab.3633 ab.386 b Mean basal area per tree.21 a.19 ab.17 abc.16 c.16 c a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. 14

20 EP964.2 Data summary for Installation 2 (Nadina District; lodgepole pine) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment.8 2 Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 24 years after planting.6 Proportion of trees Planting density 15

21 EP964.4 Data summary for Installation 4 (Skeena Stikine District; hybrid spruce) Plot layout EP964 Installation 4 Gramophone Creek Skeena Stikine Forest District Opening numbers: 93L.94 Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: 25 Installation data BEC unit SBSmc2 Lodgepole pine progeny test Location Gramophone Creek Latitude 55 Longitude ' TSA/TFL Bulkley Year established 1985 Years since planting Last measured m Least squares means and differences in response to density treatments, 25 years after planting a Planting density Variable Total volume per hectare a a a* a a Basal area per hectare a ab abc bc c Mean dbh a b bc bc c Mean height a ab ab ab b Mean volume per tree.6989 a.4192 b.298 b.2792 b.2297 b Mean basal area per tree.1822 a.1822 b.1822 b.1822 b.1822 b Mean dbh over height a b c c c Mean Annual Increment Volume per hectare a ab ab b b Basal area per hectare.353 a.4457 ab.515 bc.6244 bc.5674 c Mean dbh.5934 a.4679 b.459 bc.3844 c.3589 c Mean height.3329 a.335 a.2865 ab.2839 ab.2753 b Mean basal area per tree.17 a.15 b.13 bc.13 c.13 c a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. * Overall differences were detected, but no pair of treatments differed. 16

22 EP964.4 Data summary for Installation 4 (Skeena Stikine District; hybrid spruce) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 25 years after planting.6 Proportion of trees Planting density 17

23 EP964.5 Data summary for Installation 5 (Skeena Stikine District; lodgepole pine) Installation data BEC unit SBSdk Location Quick Latitude 54 35' Longitude ' TSA/TFL Bulkley Year established 1989 Years since planting 24 Last measured Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: Plot layout EP964 Installation 5 Quick Skeena Stikine Forest District Opening numbers: 93L Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) m Tree mortality by treatment Planting density Years after planting Least squares means and differences in response to density treatments, 24 years after planting a Planting density Variable Total volume per hectare a ab bc bc c Basal area per hectare 8.3 a ab bc bc c Mean dbh a b bc cd d Mean height Mean volume per tree.7957 a.6431 ab.5777 bc.4946 bc.4555 c Mean basal area per tree.1753 a.1386 b.119 bc.135 c.9269 c Mean dbh over height a b c cd d Mean Annual Increment Volume per hectare a b bc bc c Basal area per hectare.3333 a.538 b.6325 bc.6614 bc.8369 c Mean dbh.6118 a.5445 b.544 bc.4688 cd.4418 d Mean height Mean basal area per tree.17 a.16 b.15 bc.14 cd.14 d a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. 18

24 EP964.5 Data summary for Installation 5 (Skeena Stikine District; lodgepole pine) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 24 years after planting.8 Proportion of trees Planting density 19

25 EP964.6 Data summary for Installation 6 (Nadina District; lodgepole pine) Plot layout EP964 Installation 6 Crow Creek Nadina Forest District Opening numbers: 93L Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) Installation data BEC unit SBSmc2 Location Crow Creek Latitude 54 19' Longitude ' TSA/TFL Lakes Year established m Years since planting 24 Last measured Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: 25 Tree mortality by treatment Planting density Years after planting Least squares means and differences in response to density treatments, 24 years after planting a Variable Planting density Total volume per hectare a ab b b b Basal area per hectare a ab bc c c Mean dbh a b bc cd d Mean height Mean volume per tree.1447 a.16 b.8653 bc.7833 cd.667 d Mean basal area per tree.333 a.2129 b.185 bc.158 cd.1281 d Mean dbh over height a b c d d Mean Annual Increment Volume per hectare a ab 5.35 bc c bc Basal area per hectare.6247 a.8717 b bc c c Mean dbh.8136 a.6824 b.6265 bc.5871 cd.5251 d Mean height Mean basal area per tree.23 a.19 b.18 bc.17 cd.15 d a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. 2

26 EP964.6 Data summary for Installation 6 (Nadina District; lodgepole pine) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 24 years after planting.8 Proportion of trees Planting density 21

27 EP964.7 Data summary for Installation 7 (Central Cariboo District; lodgepole pine) Plot layout EP964 Installation 7 Skulow Lake Central Cariboo Forest District Opening number: 93A.21 Plot identification: Block # Treatment # Experimental design Completely randomized design (three replicates) Installation data BEC unit SBSdw2 Location Skulow Lake Latitude 52 17' Longitude ' TSA/TFL Williams Lake Year established 1987 Years since planting Last measured m Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: 25 Tree mortality by treatment Planting density Years after planting Least squares means and differences in response to density treatments, 26 years after planting a Planting density Variable Total volume per hectare a ab bc c d Basal area per hectare a b bc c d Mean dbh a b b b b Mean height a a a* a a Mean volume per tree.6162 a.5418 ab.4412 b.4477 b.551 ba** Mean basal area per tree.1756 a.1346 b.113 b.149 b.1128 b Mean dbh over height a b bc cd d Mean Annual Increment Volume per hectare.918 a b 2.36 bc cd d Basal area per hectare.2619 a.4587 b.5131 bc.6947 cd.935 d Mean dbh.5572 a.4899 ab.4374 b.4282 b.456 b Mean height.2835 a.3228 a.387 a.3317 ab.3891 b Mean basal area per tree.17 a.15 b.14 b.14 b.14 b a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. * Overall differences were detected, but no pair of treatments differed. ** Some switching of differences occurs. 22

28 EP964.7 Data summary for Installation 7 (Central Cariboo District; lodgepole pine) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 26 years after planting.6 Proportion of trees Planting density 23

29 EP964.8 Data summary for Installation 8 (Kamloops District; Douglas-fir) Plot layout EP964 Installation 8 Barrière Lake Kamloops Forest District Opening number: 82M.21 Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) Installation data BEC unit ICHmw3 Location Barrière Lake Latitude 51 17' Longitude ' TSA/TFL Kamloops Year established 1987 Years since planting 26 Last measured m Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: 25 Least squares means and differences in response to density treatments, 26 years after planting a Variable Planting density Total volume per hectare a ab b ba* ba** Basal area per hectare a ab b b b Mean dbh a ab bc c c Mean height a a a* a a Mean volume per tree.851 a.6881 ab.514 bc.4393 c.3599 c Mean basal area per tree.216 a.1746 ab.1285 bc.114 c.931 c Mean dbh over height a a 1.38 b 1.31 b c Mean Annual Increment Volume per hectare a ab b ba** ba** Basal area per hectare.3625 a.5857 b.6774 b.6257 b.6254 b Mean dbh.631 a.5593 ab.4715 bc.4345 c.3811 c Mean height.3953 a.3881 a.3756 a*.3415 a.3542 a Mean basal area per tree.18 a.17 ab.15 bc.14 c.13 c a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. * Overall differences were detected, but no pair of treatments differed. ** Some switching of differences occurs. 24

30 EP964.8 Data summary for Installation 8 (Kamloops District; Douglas-fir) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 26 years after planting.6 Proportion of trees Planting density 25

31 EP Data summary for Installation 9 (Rocky Mountain District; lodgepole pine) km 22 Plot layout EP964 Installation 9.1 Gold Creek Rocky Mountain Forest District Opening number: 82G.33 Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) Installation data BEC unit MSdk Location Gold Creek Latitude 49 21' Longitude 115 3' TSA/TFL Cranbrook km 24.8 Year established 1987 Years since planting 26 Last measured 213 Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: m Tree mortality by treatment Planting density Years after planting Least squares means and differences in response to density treatments, 26 years after planting a Planting density Variable Total volume per hectare Basal area per hectare a a a* a a Mean dbh Mean height Mean volume per tree Mean basal area per tree Mean dbh over height a ab bc bc c Mean Annual Increment Volume per hectare.472 a ab.9912 ab.938 ab b Basal area per hectare.1694 a.378 ab.3411 ab.3587 ab.5667 b Mean dbh Mean height Mean basal area per tree a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. * Overall differences were detected, but no pair of treatments differed. 26

32 EP Data summary for Installation 9 (Rocky Mountain District; lodgepole pine) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 26 years after planting.6 Proportion of trees Planting density 27

33 EP Data summary for Installation 11 (Rocky Mountain District; lodgepole pine) Installation data BEC unit MSdk Location Elk River Latitude 5 14' Longitude ' TSA/TFL Cranbrook Year established 1988 Years since planting 24 Last measured 212 Plot layout EP964 Installation 11 Elk River Rocky Mountain Forest District Opening number: 82J.26 Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: m 3 3 Elk River Tree mortality by treatment Planting density Years after planting Least squares means and differences in response to density treatments, 24 years after planting a Planting density Variable Total volume per hectare a ab abc c c Basal area per hectare a b c d d Mean dbh a b c cd d Mean height Mean volume per tree.7999 a.5735 b.4166 c.4224 c.3452 c Mean basal area per tree.1863 a.1335 b.118 c.9797 cd.825 d Mean dbh over height a b c d d Mean Annual Increment Volume per hectare a b b c c Basal area per hectare.3829 a.5388 b.6256 c.886 c.846 c Mean dbh.6374 a.5371 b.4662 b.461 c.423 c Mean height Mean basal area per tree.18 a.16 b.14 c.14 cd.13 d a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. 28

34 EP Data summary for Installation 11 (Rocky Mountain District; lodgepole pine) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 24 years after planting.8 Proportion of trees Planting density 29

35 EP Data summary for Installation 12 (Okanagan Shuswap District; Engelmann spruce) Plot layout EP964 Installation 12 Larch Hills Okanagan Shuswap Forest District Opening number: 82L.65 Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: 25 Installation data BEC unit ICHmw2 2 4 Location Larch Hills Latitude 5 41' 2 1 Longitude 119 1' 1 4 TSA/TFL Okanagan Year established Years since planting 24 Last measured m Least squares means and differences in response to density treatments, 24 years after planting a Variable Planting density Total volume per hectare a ab ab ab b Basal area per hectare a ab ab bc c Mean dbh Mean height Mean volume per tree Mean basal area per tree Mean dbh over height a ab bc c c Mean Annual Increment Volume per hectare.623 a.7893 ab ab ab b Basal area per hectare.284 a.35 ab.433 ab.582 b.5776 b Mean dbh Mean height Mean basal area per tree a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. 3

36 EP Data summary for Installation 12 (Okanagan Shuswap District; Engelmann spruce) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 24 years after planting.6 Proportion of trees Planting density 31

37 EP Data summary for Installation 13 (Central Cariboo District; hybrid spruce) Plot layout EP964 Installation 13 Gavin Lake Central Cariboo Forest District Opening number: 93A Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) 3 4 Installation data BEC unit ICHmk3 Location Gavin Lake Latitude 52 3' 3 3 Longitude ' TSA/TFL Williams Lake Year established Years since planting 24 Last measured 213 Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: m Windrow Least squares means and differences in response to density treatments, 24 years after planting a Variable Planting density Total volume per hectare Basal area per hectare a a a* a a Mean dbh a b b b b Mean height a b ab ab b Mean volume per tree.7338 a.2593 b.3632 b.2238 b.1986 b Mean basal area per tree.277 a.8773 b.112 b.7419 b.6664 b Mean dbh over height a b b b b Mean Annual Increment Volume per hectare Basal area per hectare.4269 a.3165 a.6386 a*.571 a.626 a Mean dbh.646 a.432 b.4697 ab.3756 b.3512 b Mean height.335 a.223 a.2717 a*.2286 a.2242 a Mean basal area per tree.19 a.14 b.15 b.13 b.13 b a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. * Overall differences were detected, but no pair of treatments differed. 32

38 EP Data summary for Installation 13 (Central Cariboo District; hybrid spruce) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 24 years after planting.6 Proportion of trees Planting density 33

39 EP Data summary for Installation 14 (Vanderhoof District; lodgepole pine) Plot layout EP964 Installation 14 Tatuk Lake Vanderhoof Forest District Opening number: 93F.7-17 Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) Installation data BEC unit SBSmc Location Tatuk Lake Latitude 53 37' Longitude 124 2' TSA/TFL Prince George Year established 1991 Years since planting 19 Last measured Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: m Tree mortality by treatment Planting density Years after planting Least squares means and differences in response to density treatments, 19 years after planting a Planting density Variable Total volume per hectare a a a* a a Basal area per hectare a ab abc bc c Mean dbh a ab ab ab b Mean height Mean volume per tree Mean basal area per tree.1124 a.875 ab.7663 ab.646 b.6119 b Mean dbh over height a b 1.58 bc c c Mean Annual Increment Volume per hectare.7554 a ab ab b b Basal area per hectare.2724 a.422 ab.5877 bc.649 bc.7844 c Mean dbh.613 a.5199 a.592 a*.459 a.4522 a Mean height Mean basal area per tree.16 a.14 ab.14 ab.13 b.13 b a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. * Overall differences were detected, but no pair of treatments differed. 34

40 EP Data summary for Installation 14 (Vanderhoof District; lodgepole pine) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 19 years after planting.6 Proportion of trees Planting density 35

41 EP Data summary for Installation 15 (Vanderhoof District; hybrid spruce) Installation data BEC unit ESSFmv1 Location Frank Lake Plot layout EP964 Installation 15 Frank Lake Vanderhoof Forest District Opening number: 93F.7-9 Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) Latitude 53 4' Longitude 124 4' TSA/TFL Prince George Year established 1991 Years since planting 22 Last measured Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: m Least squares means and differences in response to density treatments, 22 years after planting a Variable Planting density Total volume per hectare a ab ab ab b Basal area per hectare a ab abc abc c Mean dbh a ab ab b 5.49 ba** Mean height Mean volume per tree.162 a.7592 ab.6744 ab.444 b.5591 ba** Mean basal area per tree.413 a.3178 ab.2838 ab.238 b.2422 ba** Mean dbh over height a ab ab b b Mean Annual Increment Volume per hectare.2141 a.3297 ab.415 ab.3482 b.583 b Basal area per hectare.858 a.1397 ab.1755 bc.1638 bc.2558 c Mean dbh.2995 a.2669 ab.2449 ab.26 b.228 ba** Mean height Mean basal area per tree.12 a.11 ab.11 ab.11 b.11 ba** a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. ** Some switching of differences occurs. 36

42 EP Data summary for Installation 15 (Vanderhoof District; hybrid spruce) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 22 years after planting.8 Proportion of trees Planting density 37

43 EP Data summary for Installation 16 (Headwaters District; Douglas-fir) Plot layout EP964 Installation 16 Adams River Headwaters Forest District Opening number: 82M Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: 25 Installation data BEC unit ICHmw Location Adams River Latitude 51 27' Longitude ' TSA/TFL Kamloops Year established Years since planting Last measured m Least squares means and differences in response to density treatments, 21 years after planting a Variable Planting density Total volume per hectare a ab bc c c Basal area per hectare a a b b b Mean dbh a a a* a a Mean height Mean volume per tree Mean basal area per tree.9644 a.6678 ab.827 ab.759 ab.5529 b Mean dbh over height a ab bc cd d Mean Annual Increment Volume per hectare.6754 a.845 a b b b Basal area per hectare.285 a.2839 a.5276 b.611 b.6126 b Mean dbh.4891 a.467 a.459 a*.4228 a.3759 a Mean height Mean basal area per tree.15 a.13 ab.14 ab.13 ab.13 b a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. * Overall differences were detected, but no pair of treatments differed. 38

44 EP Data summary for Installation 16 (Headwaters District; Douglas-fir) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 21 years after planting.6 Proportion of trees Planting density 39

45 EP964.2 Data summary for Installation 2 (Okanagan Shuswap District; lodgepole pine) Installation data BEC unit ESSFxc Location Home Lake Latitude 5 4' Longitude ' TSA/TFL Okanagan Year established 1993 Years since planting 2 Last measured 213 Plot layout EP964 Installation 2 Home Lake Okanagan Shuswap Forest District Opening number: 82L.7-16 Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: m Tree mortality by treatment Planting density Years after planting Least squares means and differences in response to density treatments, 2 years after planting a Planting density Variable Total volume per hectare a b c cd d Basal area per hectare a b c d d Mean dbh a b bc bc c Mean height Mean volume per tree.329 a.249 ab.2375 ab.2134 b.1762 b Mean basal area per tree.116 a.8571 b.8177 bc.7356 bc.611 c Mean dbh over height 2.36 a b bc c c Mean Annual Increment Volume per hectare.7492 a b c c c Basal area per hectare.2721 a.485 b.568 c.6729 cd.729 d Mean dbh.5944 a.595 b.4928 b.4698 bc.4258 c Mean height Mean basal area per tree.16 a.14 b.14 bc.14 bc.13 c a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. 4

46 EP964.2 Data summary for Installation 2 (Okanagan Shuswap District; lodgepole pine) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 2 years after planting.6 Proportion of trees Planting density 41

47 EP Data summary for Installation 23 (Arrow Boundary District; hybrid spruce) Plot layout EP964 Installation 23 Grano Creek Arrow Boundary Forest District Opening number: 82E.57 Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: 25 Installation data BEC unit MSdm1 Location Grano Creek Latitude 49 33' Longitude ' TSA/TFL Boundary Year established 1995 Years since planting 18 Last measured m Least squares means and differences in response to density treatments, 18 years after planting a Variable Planting density Total volume per hectare 8.24 a ab ab b ba** Basal area per hectare a ab abc c c Mean dbh Mean height Mean volume per tree.1781 a.13 ab.8146 ab.9151 ab.663 b Mean basal area per tree.5667 a.3493 ab.374 ab.3321 ab.2627 b Mean dbh over height Mean Annual Increment Volume per hectare.4114 a.5233 a.6421 a*.9716 a.9136 a Basal area per hectare.1328 a.1795 ab.2439 ab.3571 b.3654 b Mean dbh Mean height Mean basal area per tree.13 a.12 ab.12 ab.12 ab.11 b a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. * Overall differences were detected, but no pair of treatments differed. ** Some switching of differences occurs. 42

48 EP Data summary for Installation 23 (Arrow Boundary District; hybrid spruce) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) only one value in one measurement Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 18 years after planting.6 Proportion of trees Planting density 43

49 EP Data summary for Installation 24 (Okanagan Shuswap District; Douglas-fir) Plot layout EP964 Installation 24 Mt. Ida Okanagan Shuswap Forest District Opening number: 82L.64 Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) Installation data BEC unit ICHmw2 Location Mt. Ida Latitude 5 37' Longitude ' TSA/TFL Okanagan Year established 1996 Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: Years since planting 17 Last measured m Least squares means and differences in response to density treatments, 17 years after planting a Variable Planting density Total volume per hectare a a a* a a Basal area per hectare a ab ab ab b Mean dbh a ab 1.73 abc bc c Mean height Mean volume per tree.3631 a.3297 a.3422 ab.224 ab.2498 b Mean basal area per tree.121 a.95 ab.8683 abc.6217 bc.6516 c Mean dbh over height a ab 1.64 ab b.9731 b Mean Annual Increment Volume per hectare.8599 a ab b b b Basal area per hectare.2443 a.4416 ab.6164 b.5663 b.724 b Mean dbh.6644 a.6291 ab.6261 ab.512 ab.529 b Mean height Mean basal area per tree.16 a.16 ab.15 abc.14 bc.14 c a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. * Overall differences were detected, but no pair of treatments differed. 44

50 EP Data summary for Installation 24 (Okanagan Shuswap District; Douglas-fir) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) only one value in one measurement Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 17 years after planting.8 Proportion of trees Planting density 45

51 EP Data summary for Installation 25 (Okanagan Shuswap District; western larch) Plot layout EP964 Installation 25 Hidden Lake Okanagan Shuswap Forest District Opening number: 82L.56 Plot identification: Block # Treatment # Experimental design Randomized complete block design (three blocks) Installation data BEC unit ICHmw2 Location Hidden Lake Latitude 5 32' Longitude ' 2 3 TSA/TFL Okanagan Year established 1997 Years since planting 16 Last measured Treatment 1: 5 Treatment 2: 1 Treatment 3: 15 Treatment 4: 2 Treatment 5: m Least squares means and differences in response to density treatments, 16 years after planting a Variable Planting density Total volume per hectare a b b b b Basal area per hectare a b b b c Mean dbh a ab 1.73 abc c c Mean height Mean volume per tree.3631 a.3297 ab.3422 abc.224 c.2498 c Mean basal area per tree.121 a.95 ab.8683 abc.6217 c.6516 c Mean dbh over height a b 1.64 c c.9731 c Mean Annual Increment Volume per hectare.8599 a b b b b Basal area per hectare.2443 a.4416 b.6164 bc.5663 bc.724 c Mean dbh.6644 a.6291 ab.6261 abc.512 c.529 c Mean height.515 a.5239 a.5771 a*.485 a.5177 a Mean basal area per tree.16 a.16 ab.15 abc.14 c.14 c a Planting densities with same letter are not significantly different (α =.5). If no letters appear after the number, then no differences were detected among the treatments. * Overall differences were detected, but no pair of treatments differed. 46

52 EP Data summary for Installation 25 (Okanagan Shuswap District; western larch) Continued Mean dbh, mean height, mean annual volume increment (MAI) per tree, and mean crown ratio versus years after planting by treatment Mean dbh (cm) MAI volume (m 3 ) Mean height (m) Mean crown ratio (%) only one value in one measurement Total volume and basal area per hectare versus years after planting by treatment Total volume per ha (m 3 ) Basal area per ha (m 2 ) dbh class (cm) 1: < 6 2: 6 1 3: : : : > 22 Proportion of trees by dbh class and treatment, 16 years after planting.6 Proportion of trees Planting density 47