Alaska Extension Review

Transcription

1 Alaska Extension Review 1997 Trial Season Alaska Cooperative Extension University of Alaska Fairbanks Fairbanks, Alaska April 1998 Dr. Robert Wheeler, Editor Extension Forestry Specialist 308 Xanana Loop, P.O. Box University of Alaska Fairbanks Fairbanks, AK (907) /6363

2 GROWTH AND ADAPTABILITY OF AFOGNAK AND JUNEAU SITKA SPRUCE PROVENANCES ON AFOGNAK ISLAND, ALASKA1 by John N. Alden, Affiliate Research Professor, University of Alaska Fairbanks COOPERATORS: LOCATION: Koncor Forest Products, Inc., Anchorage Alaska, U.S. Forest Service, PNW Research Station, Portland Oregon U.S. Forest Service Unit 32 (58 16' N. Lai; ' 30" W. Long.) near Portage Lake, 1100 Road, Afognak Island FUNDING SOURCE: U.S. Forest Service, PNW Research Station, Forest Sciences Laboratory, Juneau, and Institute of Northern Forestry, Fairbanks, Alaska; Koncor Forest Products, Inc., Anchorage, Alaska OBJECTIVE: METHODS: To determine if the growth, size, and vigor of Sitka spruce (Picea sitchensis (Bong.) Carr.) forests on Afognak Island, SW Alaska can be improved by introducing populations from comparable latitudes and altitudes in SE Alaska. Open-pollinated Sitka spruce seed from Afognak Island, and from 58 25' North Latitude near Juneau, and about 30 miles east of Excursion Inlet were sown in the U.S. Forest Service container nursery at Beaver Creek, Oregon in 1977 (Harris 1978). The Juneau provenance (seed source) was about 650 miles east of the experimental site on Afognak Island. In May 1978, 70 seedlings of each provenance were planted and staked at about three meter spacing in 14, ten tree rows of alternating single tree plots in Unit 32, Afognak Island. The experimental site was logged within two years of planting and was not prepared. Micro-sites between adjacent planting spots were heterogeneous, but the soils were undisturbed. Survival and height of each seedling was measured annually from 1977 to In 1990, the experiment was measured for tree height, stem diameter outside bark in millimeters at 15 centimeters, and at breast height (dbh, 137 centimeters). Foliage color, forked and broken tops, and incident of severe needle cast disease, probably Lirula macrospom (Hartig) Darker (Holsten et al. 1985) were also recorded. The study was remeasured in May 1994 for tree height in 0.5 decimeters, stem dbh outside bark and at 15 centimeters in millimeters, and incident of broken tops or forking, needle cast disease, blue, blue-green and green foliage, and cone production. Needle cast disease was scored as present 1) moderate defoliation 'Revised from an unpublished report "Field Research on Genetic Variation Among Sitka Spruce Provenances from the Gulf of Alaska and Wind-Pollinated Families on Afognak Island from 1978 to 1994; and on Seed Shelter Trials in 1994" on file with the author, School of Agriculture and Land Resources Management, University of Alaska Fairbanks. 50 Alaska Cooperative Extension

3 2) severe defoliation, and 3) stem diameter of each tree at ground level was extrapolated from dbh. Total stem volume, including bark, was approximated from the volume of a cone, v=l,0472r2h; where r is stem radius at ground level, and h is tree height in centimeters. Provenance differences in tree height, dbh, and stem volume (quantitative traits) were tested from 95% confidence intervals (p<0,05) about the study (sample) means. Differences between provenances in numbers of dead or missing trees, cone producing trees, and broken tops and forking (non-parametric data) were tested with chi-square analyses of a (2x2) contingency table. Provenance frequencies in needle cast disease and foliage color were tested with the G-test of independence in a (2x3) contingency table (Sokal and Rohlf 1969). RESULTS: In 1990, twelve growing seasons after planting, the Juneau provenance was 15% taller, 17% larger in dbh, and had 24% (1014 cm3) more stem volume per tree than the Afognak provenance (Table 1). All growth differences were significant. Trees with unusual light green foliage in were more frequent for the Juneau provenance (38%) than the Afognak provenance (11%) at p< Frequency of broken and forked tops (11% Afognak; 16% Juneau), and incident of severe needle cast disease (3% Afognak; 3% Juneau) were not statistically different. Table 1. Mean dbh, Height, Stem Volume, and 95 Percent Confidence Limits for Afognak Island and Juneau Provenances in Unit 32, Afognak Island in June 1990 and May 1994 (number of sample trees is in parentheses) Trait Afognakblue race 95 percent confidence limit Juneaugreen race 95 percent confidence limit 89VOL/tree (cm3) 89DBH (mm) 89HT (cm) 4153(37) ±647.0 ±4,5 ±17,0 5167(37) ±764,0 ±4.6 ± VOL/tree (cm3) 93DBH (mm) 93HT (cm) 8646 (46) ± ±5.8 ± (52) ± ±6,7 ±33.0 2At first sight, the light green foliage of the Juneau provenance appeared unhealthy, an indication of environmental stress and maladaptation. Later, the dense foliage and fast growth of the Juneau provenance suggested that it was as well adapted as the Afognak provenance. To confirm naturalization of a population introduced to a new environment, it should complete one life cycle and establish offspring in competition with the local vegetation Alaska Extension Review 51

4 By the end of 1993, sixteen growing season after planting/ the Juneau provenance was 27% taller, 38% larger at dbh, and had 87%, or 6259 cm3, more stem volume per tree than the Afognak provenance. All differences between the" provenances in growth traits were statistically significant in both 1990 and After mortality stabilized in 1980 (Figure 1), growth rates and differences between the provenances increased exponentially (Figure 2). Survival (71 % Afognak; 76% Juneau)4, frequency of broken and forked tops (11% Afognak; 23% Juneau), and trees with needle cast disease (moderate to severe infection: 10% Afognak; 5% Juneau) were not statistically different between the provenances in May Infected foliage was evident on all trees, but severity of the disease was difficult to judge because winter rain, snow and wind had removed most of the dead needles before spring. The inner foliage on branches and twigs of the Afognak source was missing, probably from the needle cast disease. The outer needles were shorter than the needles of the Juneau source, and were often upturned. Needles of the Juneau source were flattened on the branch, and the lower surfaces were white with prominent stomatal rows. In addition, Juneau needles were sharper at the apex and more rigid than Afognak needles. In May 1994, only cone production and foliage color were significantly different between the provenances (p<0.005). Twenty percent of the Afognak and zero percent of the Juneau trees produced cones. The foliage of 94 percent of the Afognak trees was blue; two percent of the trees were blue-green and four percent were green. At the same time, 88 percent of the Juneau trees were green, four percent were blue-green and eight percent were blue. DISCUSSION: Foliage color of Sitka spruce is more variable in SE Alaska than SW Alaska. In a recent greenhouse test on Mitkof Island (Copes et al. 1996), five year-old clones of ortets (parents) selected for green foliage grew 17% taller than clones of ortets selected for blue color. Ninety-four and 90 percent of the rooted cuttings retained the green and blue foliage of their ortets in the field, respectively, and 98 and 66 percent retained their green and blue colors in a greenhouse. These results indicated that foliage color of Sitka spruce has a strong genetic basis, and is related to tree growth and size. Site index (tree height at 100 years) of Sitka spruce in Prince William Sound and SW Alaska is 10 to 12 meters (32 to 40 feet) less than predicted by latitude and growing season temperature (Farr and Harris 1979). Seedling height, stem diameter, date of annual growth cessation, and length of the growing period were negatively correlated with latitude and longitude of Sitka spruce provenances from SE to SW Alaska in nursery and field environments (Aid en and 3To confirm growth differences between the Afognak and Juneau provenances, ten 20 year-old Afognak trees were paired with nine Juneau trees in an operational planting and measured for height and dbh on June 12,1997. The planting was in Unit 25,1100 Main Road. The Juneau trees were 30 percent taller (7.2±1.4 vs 5.5±1.0 m), 55 percent larger in dbh (16.4±4.1 vs 10.6±2.6 cm), and averaged nearly three times more stem volume per tree ( vs 0, m3) than the Afognak trees. The Afognak trees were planted and staked in October, 1977 for comparison with 20,000 Juneau seedlings. The seedlings were raised at the Alaska Forest Tree Nursery, Palmer in 1977 (Fultz 1978, Kerr 1978). 4At five planting spots (plots), trees of the Afognak provenance could not be distinguished from natural regeneration, and their data were eliminated from the study. 52 Alaska Cooperative Extension

5 SURVIVAL OF SITKA SPRUCE PROVENANCES on Afognak Island 03 a. '1* Year Afognak Provenance * Juneau Provenance Figure 1, Survival of Sitka pruce Provenances in Unit 32, Afognak Island from May 1978 (1977 growing season) to May 1994 (1993 growing season) GROWTH OF SITKA SPRUCE PROVENANCES on Afognak Island to " X Year Afognak Provenance * Juneau Provenance Figure 2, Difference in Yearly Mean Height Growth Between the Juneau and Afognak Provenances in Unit 32, Afognak Island. Height Difference Increased Exponentially After Mortality Declined in Alaska Extension Review 53

6 Loopstra 1988). These results demonstrated that in migrating from SE to SW Alaska, Sitka spruce adapted to shorter growing seasons, grew less, and lost inherent productivity. In spite of record low temperatures in September 1992, the Juneau provenance was as well adapted to Unit 32, Afognak Island 16 years after planting as the local Afognak provenance. The size, survival, and vigor of the Juneau provenance suggest that the green race of Sitka spruce from comparable latitudes and altitudes in southeast Alaska may increase the growth of Sitka spruce on Afognak Island. CONCLUSION: REFERENCES: The Afognak Island provenance experiment demonstrated that foliage color of Sitka spruce is determined by provenance, and the slow-growing blue phenotype of Afognak Island is racially distinct from the tall green phenotype of the Juneau provenance. To establish the best provenance zones for Sitka spruce in SW Alaska, additional provenances from 52 to 60 north latitude and from sea level to altitude tree limits should be field tested on Afognak and Kodiak Islands, and on the Pacific Coast of the Alaska Peninsula from Cook Inlet to Unalaska. Alden, John and Elaine Loopstra Progress Report: Establishment of trees and shrubs on Naval Air Station, Adak Island, Alaska U.S.D.A. Forest Service, Pacific Northwest Research Station. Institute of Northern Forestry, Fairbanks, Alaska, and U.S. Department of Navy, Pacific Northwest Naval Facilities Engineering Command, Poulsbo, Wash. 39 p. Unpublished report on file at the U.S. Forest Service Library, Forest Sciences Laboratory, 2770 Sherwood Lane, Juneau, Alaska, and the Rasmuson Library, University of Alaska, Fairbanks. Copes, D. L., W. H. Pawuk, WA,, Farr, and R. R, Silen, Relation of crown and foliage traits to height growth of Sitka spruce. Western Journal of Applied Forestry 11(3): Farr, Wilbur, A. and A.S. Harris Site index of Sitka spruce along the Pacific Coast related to latitude and temperatures. Forest Science 25: Fultz, Clark M Unit 25 "study/' Letter to reforestation information files: U.S. Forest Service Report, Chugach National Forest, Anchorage, Alaska. 2 pp. Harris, A. S Study Plan: Reciprocal planting of Sitka spruce seed sources; Afognak Island and Juneau, Alaska. Unpublished. U.S.D.A. Forest Service. Forest Sciences Laboratory, 2770 Sherwood Lane, Juneau, Alaska. 6 pp. Holsten, Edward H., Paul E. Hennon, and Richard A, Werner Insects and Diseases of Alaskan Forests. U.S.D.A. Forest Service. Alaska Region Report Number 181. Juneau, Alaska. 217 pp. Kerr, Cal. 1978, Afognak Island planting, 1977, August 11,1978 instructions to Joe Stehlik, Nursery Manager, Palmer, Alaska. Alaska Department of Natural Resources, Division of Forestry. Anchorage, Alaska. 4 pp. 54 Alaska Cooperative Extension

7 Sokal, R, Robert and E James Rohlf. 1969, Biometry: The Principles and Practice of Statistics in Biological Research, (pages ). First Edition. W. H. Freeman and Co., San Francisco, CA. 776 pp. NOTE: The assistance of Dr. Robert A. Wheeler, Extension Forester, Alaska Cooperative Extension Service, in evaluating the growth of Afognak and Juneau Sitka spruce provenances in Unit 25, Afognak Island, and reviewing the content and accuracy of this report is appreciated Alaska Extension Review 55