MANAGEMENT NOTES Number 22

Transcription

1 MANAGEMENT NOTES Number 22 Camp Tamawaby European Larch The History of a Plantation by W. M. Glen and H. A. Isherwood 1999 Background In the autumn of 1998 the largest plantation of European larch (Larix decidua) in Prince Edward Island was harvested. This note gives a history of the plantation from a variety of sources including nursery records, District records, Permanent Sample Plots measurements and recollections of Forestry Service staff. Figure I, CampTamawaby European Larch 27 th June 1991 photo courtesy of Peter Neily, Nova Scotia Department of Natural Resources This is a publication of the P.E.I. Department of Agriculture and Forestry, Forestry Division Establishment

2 WELLINGTON WELLINGTON CENTRE DAYS CORNER CROSS RIVER McNiells Point Thompsons Point Baglole Point In 1959 the Forestry Division nursery at Beach Grove produced the crop of European larch which was planted at Grand River, Prince County, in what is now the Camp Tamawaby Demonstration Woodlot (Provincial property number 66001). See Figure II for the location. This planting was recorded as being 3.7 ha. in area although the measured area was 4.1 hectares. The seed is believed to have come from Herbst Brothers Seedsmen Inc. of New York. The records for this company have not survived but according to Roy Herbst, son of the former principle of Herbst Brothers Seedsmen, most of the collections of European larch sold by the company in the 1950s and 1960s came from New York State. The origin of the New York plantations is not known (Glen, 1994). The stock from the nursery is suspected to have been 2+0 bareroot stock as that was what the 1954 larch crop had been. CROSS RIVER WELLINGTON CENTRE Camp Tamawaby European larch Plantation E WELLINGTON DAYS CORNER Figure II: Location of 1959 European Larch plantation in the Camp Tamawaby Demonstration Woodlot, Prince County, Prince Edward Island The site was formerly agricultural land and no indication of any site preparation was evident and no records survive to indicate that any was done. The planting density was 3000 stems per hectare or approximately a 6' by 6' spacing. There are no records of any maintenance or other activity and the plantation was forgotten about until the development of the Demonstration Woodlot in 1980 when the plantation was rediscovered. At the time of rediscovery the plantation had no large gaps and was well stocked with a density of 2225 stems/ha. Midlife In 1982 a road was built through the plantation and along the eastern and northern sides. The road resulted in 0.12 hectares of the stand being harvested. The part of the plantation to the north of the new road was divided into three parts and two blocks were thinned from approximated 2225 stems/ha to 1075 stems/ha and 750 stems/ha. In 1984 permanent sample plots of 1/25 of a hectare each were established in the three blocks (P.S.P. numbers 196a, 196b, 196e). Table I provides a summary of the plantation in

3 Table I European larch Camp Tamawaby 1984 aged 25 years 6' by 6' ' by 10' ' by 12' The permanent sample plots were remeasured in 1990, 1992, 1993, 1996 and The summary information from the P.S.P.s are shown in Tables II-VI Table II European larch Camp Tamawaby 1990 aged 31years 6' by 6' ' by 10' ' by 12' Figure III, CampTamawaby European Larch 6' by 6' spacing 27 th June 1991 photo courtesy of Peter Neily, Nova Scotia Department of Natural Resources Table III European larch Camp Tamawaby 1992 aged 33 years 6' by 6' ' by 10' ' by 12'

4 Table IV European larch Camp Tamawaby 1993 aged 34 years 6' by 6' ' by 10' ' by 12' In the summer of 1993, 2.32 ha. of the plantation was thinned by a contractor and approximately 27 m 3 /ha of larch and the suppressed spruce understory were removed. Unfortunately the exact volumes removed were not recorded. The P.S.P. was remeasured before the thinning (Table IV). Table V European larch Camp Tamawaby 1996 aged 37 years 6' by 6' ' by 10' ' by 12' Table VI European larch Camp Tamawaby 1998 aged 39 years 6' by 6' ' by 10' ' by 12' Tree Diameter The average tree diameter at breast height (DBH) was determined by the P.S.P. measurements. Table VII shows the DBH at each measurement. As a result of the thinning the average diameter of the trees in the thinned plots were significantly larger than the trees in the initially unthinned plot. 4

5 Table VII Average merchantable tree diameter at breast height tree spacing age 6' by 6' 10' by 10' 12' by 12' * * after the thinning removed the smaller trees plus 3 years growth Site Quality Site index, measured as the height in metres at breast height age of 50 years, was determined to be 19. This is considered to be an average site quality for larch. General yield class (GYC) is used by the British Forestry Commission (Hamilton and Christie, 1971) as a measure of the maximum mean annual increment that the plantation will reach during a rotation. It is based on the height\age relationships and volume increment developed from permanent sample plots. This plantation has been calculated from its height growth to be GYC 8. Again this is considered to be an average site quality. GYC 8 means the maximum increment that the plantation is expected to reach is 8 m 3 /ha/yr. (See Glen, 1992 for comparison information from other larch plantations.) Damaging Agencies In 1992 European Larch canker (Lachnellula wilkommii) was found at Days Corner, approximately 3 kilometres south-south west of Camp Tamawaby. In 1994 the canker was found in a native larch stand in the woodlot and in February of 1996 it was found in the European larch stand. When the stand was harvested in 1997 branch and stem cankers were found in the tree crowns. The oldest canker was thirteen years of age indicating the canker had been in the stand since The canker had not caused any problems with regard to volume growth. No trees had been seriously effected and there was no mortality due to the canker. In the mid 1990s a few trees along the southern edge of the stand facing the woodlot road were attacked by the larch beetle (Dendroctonus simplex) and some mortality occurred. The trees were removed but each year one or two more trees succumbed to the beetle. Final Harvest With the loss of vigour of the individual trees in the stand, due primarily to the small live crown ratio, the increased number of trees succumbing to the larch beetle and concern regarding larch canker, the decision was reached to harvest the stand. The stand was harvested over a three year period by government crews. In the.964 ha. area to the south of the road, the harvest in 1997 produced m 3 (60.9 cords) with a product breakdown of 35.3 m 3 (14.7 cords) of firewood, 68.9 m 3 (28.7 cords) of 5

6 studwood* and 42.0 m 3 (17.5 cords) of sawlogs. (*Note the definition of studwood was a small end diameter of greater than 15 cm (6"). The two thinned areas were harvested in the summer of An area of 1.75 hectares produced a volume of m 3 (122.1 cords) with a product breakdown of 81.6 m 3 (34 cords) of firewood, m 3 (44.7 cords) of studwood and m 3 (43.4 cords) of logs. The 1.26 ha. of the control area harvested in the spring/summer of 1999 produced a total of m 3 ( cords) of wood. The product breakdown was 49.2 m 3 (20.51 cords) of firewood, 95.7 m 3 (39.89 cords) of studwood and m 3 (60.61 cords) of sawlogs. The total volume removed from the plantation north of the woodlot road (excluding the trees removed by thinnings) was m 3 or cords. The production was m 3 /ha or 32.2 cords/acre. The product mix of the final harvest was firewood/pulpwood 22.7%, studwood 37.3% and sawlogs 40.0%. Figure IV; Harvested European Larch logs form Camp Tamawaby, August 1999 photo by H. A. Isherwood Comparison with British Yield Tables As mentioned earlier the British Forestry Commission s Yield Models for Forest Management (Edwards, 1981) general yield class curves for European larch show that the average height of the dominant trees in this plantation put it into the upper part of General Yield Class 8. The volume increment for the Permanent Sample Plots for the period age 25 to age 39 were 7.5 m 3 /ha/yr, 7.5 m 3 /ha/yr, and 7.9 m 3 /ha/yr respectively for the three spacings, 6' by 6', 10' by 10' and 12' by 12'. (The 6' by 6' spacing s increment includes the estimated volume removed in the 1993 thinning.) This compares favourably with the expected yield of 8 m 3 /ha/yr. The volume increment of the three spacings was relatively constant but the increment of the individual trees in the control was much less than in the wider spacings. This is a reflection of the greater number of trees and the small crown size on those trees. Hamilton & Christie (1971) and Rollinson (1985) recommend first thinning of European larch when the basal area of the 6

7 stand reaches 22 m 2 /ha. When this stand was thinned in 1983 the basal area was 32 m 2 /ha or almost 50% higher. However, the recommended age for first thinning for GYC8 is years which was the case for this plantation (with the exception of the control block). The 10' by 10' spacing block The thinning in 1983 to the 1075 and 750 stems per hectare was done at approximately the correct time. The British Forestry Commission s yield model R 39c, (Edwards, 1981) show that the number of stems per hectare should be reduced from 2670 to1190 at age 22. This very similar to what was done with the 10' by 10 block (2225 to 1075 stems/ha). The yield model however has further thinnings down to 831 stems/ha., at age 27; 640, at age 37; and 434, at aged 42. This plantation had no further thinning done in the blocks that were thinned in The volume of the standing crop when the 10' by 10 block was harvested at aged 39 was 231 m 3 /ha. This compares with 160 m 3 /ha of the standing crop in the yield tables. The yield tables also record a cumulative volume (from the standing crop and thinnings) of 272 m 3 /ha. This compares to the estimated cumulative volume of 247 m 3 /ha (231 m 3 /ha+16 m 3 /ha) that was obtained. The difference between the two total volumes of 25 m 3 /ha is the volume lost from the lack of subsequent thinning. The 12' by 12' spacing block This block had an estimated cumulative volume of 251 m 3 /ha (208 m 3 /ha at harvest plus 43 m 3 /ha from the 1983 thinning). This wider spacing in1983 left some of the site unoccupied so there were not enough trees to fully utilize the site. The unthinned block The block which was not thinned in 1983 had its number of stems per hectare reduce by mortality from 2,225 at age 25 to 1,600 at age 34. The thinning in 1993 at age 34 reduced the stem count to 900 and by age 39 it had dropped to 875. The thinning in 1993 primarily removed suppressed and dead larch so the volume removed has not been include in the total volume. The volume in this block at age 39 was 220 m 3 /ha Unfortunately the British Forestry Commission s yield models do not have a model for unthinned European larch but there was one for unthinned Japanese/hybrid larch GYC8 (model F125c). In this model the total volume would be 287 m 3 /ha at age 39. However comparison between thinned Japanese larch and European larch (models R39b and R42a) showed that the European larch produced 20% less volume. When this is applied to expected yield it is reduced to 230 m 3 /ha which is comparable to the 220 m 3 /ha as measured by the P.S.P. The British yield models appear to be applicable to European larch grown on Prince Edward Island. Special Studies In 1993 a number of trees were harvested to produce logs as part of an evaluation of wood properties (Peters, 1994). The 26 trees averaged 21.3 cm in diameter (range cm) and were cut into 3 metre logs. The logs were transported to the Wood Science and Technology Center in Fredericton where the study was conducted (see Figure V). The logs were sawn and the grading results showed that the trees from this plantation were 9% selects, 59% Number 1 and 32% number 2. 7

8 Figure V, The load of logs from Camp Tamawaby taken to the Wood Science and Technology Center in Fredericton photo by Wade MacKinnon The study which also included logs from four other sites in the Maritime Provinces concluded that specific gravity of European larch was higher than white spruce, Norway spruce and balsam fir. It also had longer fibers and better bending propertied than some other softwoods. Structural select grades were low due to large knot size and visual defects. Pruning of the crop trees to a height of three metres would have increased the amount of select grade lumber. References: Edwards, P. N., 1981; Yield Models for Forest Management, Forestry Commission Booklet 48, Her Majesty's Stationary Office, London. Glen, W.M., 1992; Growth & Survival of Exotic Larix in Prince Edward Island, a Status Report Management Note Number 2, Department of Energy and Forestry, Forestry Division, Charlottetown, P.E.I. Glen, W.M., 1994; Seed Sources used in Prince Edward Island Plantations , Management Note Number 6, Department of Energy and Forestry, Forestry Division, Charlottetown, P.E.I. Hamilton, G.J. and Christie, J.M., 1971, Forest Management Tables (Metric), Forestry Commission Booklet No. 34, Her Majesty's Stationary Office, London. Peters, G. M., 1994; Evaluation of Properties of Exotic Larch grown in Eastern Canada and the North-Eastern United States, Wood Science and Technology Centre, University of New Brunswick, Hugh John Fleeming Forestry Centre, R.R. No. 10, Fredericton, New Brunswick E3B 6H6. Rollinson, T.J.D., 1985, Thinning Control, Forestry Commission Booklet No. 54, Her Majesty's Stationary Office, London. 8

9 CampTamawaby European Larch 27 th June 1991 photo courtesy of Peter Neily, Nova Scotia Department of Natural Resources Permanent Sample Plot Measurements by; Mike Bradley, Joey Carroll, Jon Hutchinson, Blair Mallard, Peter Sharkey. Harvest was supervised by; Edwin Gillis, and Brent McLean and carried out by; Mark Arsenault, David Hunter, Arnold Madsen, Tom DesRoches, Edward Sharbell, and Employment Development Agency Crews 9