Community dynamics in old growth and second growth hemlock forests

1. Community dynamics in old growth and second growth hemlock forests

2. Questions • What impact, if any, is the hemlock woolly adelgid having on eastern hemlocks in North Carolina? • Are other tree species responding with respect to relative density, relative basal area or importance value? • How does species richness increase with area in eastern hemlock forests? • How does the species area relationship change over time in eastern hemlock forests?

3. Field sites of second growth and old growth hemlock communities in western North Carolina Plots 11 Second growth Ave. Elev: 2617 ft 12 Old growth Ave. Elev: 3045 ft Great Smoky Mountains National Park Second growth Old growth Joyce Kilmer Memorial Forest Highlands Ranger District

4. Carolina Vegetation Survey protocol 10 total modules for trees 4 intensively sampled modules for herbs 20 m 50 m

5. Intensively Sampled Module 10 cm 30 cm 1 m 3.3 m 10 m

6. Questions • What impact, if any, is the hemlock woolly adelgid having on eastern hemlocks in North Carolina? • Are other tree species responding with respect to relative density, relative basal area or importance value? • How does species richness increase with area in eastern hemlock forests? • How does the species area relationship change over time in eastern hemlock forests?

7. Life history of the hemlock woolly adelgid • The hemlock woolly adelgid has two hosts: • Tsuga sp. • Passive dispersal • Asexual reproduction • Density dependent shift to a winged sexuperae • Picea sp. • Winged sexuperae • Sexual reproduction • No native spruce are suitable hosts • This results in two waves of mortality in hemlock with the smaller hemlocks dying first.

8. Average change in abundance of small (0 – 2.5 cm dbh) individuals -30 -20 Average change in abundance -10 * * 0 -10 Old Growth Second Growth Kalmia lat Tsuga can Tsuga can Acer rub Acer rub Betula len Betula len Rhodo max Rhodo max Kalmia lat

9. Questions • What impact, if any, is the hemlock woolly adelgid having on eastern hemlocks in North Carolina? • Are other tree species responding with respect to relative density, relative basal area or importance value? • How does species richness increase with area in eastern hemlock forests? • How does the species area relationship change over time in eastern hemlock forests?

10. Relative density, relative basal area and importance value in old growth forests Relative Value * Betula lenta Acer rubrum Kalmia latifolia Tsuga canadensis Rhododendron maximum

11. Relative density, relative basal area and importance value in second growth forests * * Relative Value Betula lenta Acer rubrum Kalmia latifolia Tsuga canadensis Rhododendron maximum

12. Summary of successional change in tree layer • Small hemlocks are decreasing in absolute abundance in both old growth and second growth forests, with no corresponding increase in larger size classes. • In old growth forests, Rhododendron maximum is increasing in relative abundance. • In secondary growth forests, Tsuga canadensis is increasing in relative abundance and importance values.

13. Questions • What impact, if any, is the hemlock woolly adelgid having on eastern hemlocks in North Carolina? • Are other tree species responding with respect to relative density, relative basal area or importance value? • How does species richness increase with area in eastern hemlock forests? • How does the species area relationship change over time in eastern hemlock forests?

14. Carolina Vegetation Survey protocol 10 total modules for trees 4 intensively sampled modules for herbs 20 m 50 m

15. Species richness at 1000 m2

16. Average species richness in old growth hemlock forests at increasing scales (m2) Pre-adelgid Post-adelgid 0.01 0.1 1.0 10 100 1000 0.01 0.1 1.0 10 100 1000

17. Average species richness in second growth hemlock forests at increasing scales (m2) Pre-adelgid Post-adelgid 0.01 0.1 1.0 10 100 1000 0.01 0.1 1.0 10 100 1000

18. Average change in species richness at increasing scales in old growth and second growth hemlock forests Old Growth Second Growth * * 0 Average change in species richness 0.01 0.1 1.0 10 100 1000 0.01 0.1 1.0 10 100 1000

19. Questions • What impact, if any, is the hemlock woolly adelgid having on eastern hemlocks in North Carolina? • Are other tree species responding with respect to relative density, relative basal area or importance value? • How does species richness increase with area in eastern hemlock forests? • How does the species area relationship change over time in eastern hemlock forests?

20. Species-area relationships in hemlock forests before the hemlock woolly adelgid Log10 species richness Pre-adelgid, old growth Log10 area

21. Species-area relationships in hemlock forests before the hemlock woolly adelgid Log10 species richness Pre-adelgid, second growth Log10 area

22. Species-area relationships in hemlock forests before the hemlock woolly adelgid Log10 species richness Pre-adelgid, old growth Pre-adelgid, second growth Log10 area

23. Species-area relationships in hemlock forests before the hemlock woolly adelgid Log10 species richness Pre-adelgid, old growth Pre-adelgid, second growth Log10 area

24. Species-area relationships in hemlock forests after the hemlock woolly adelgid Log10 species richness Post-adelgid, old growth Post-adelgid, old growth Post-adelgid, second growth Post-adelgid, second growth Log10 area

25. Species-area relationships in hemlock forests after the hemlock woolly adelgid Log10 species richness Post-adelgid, old growth Post-adelgid, second growth Log10 area

26. Change in the species area relationship over time in old growth forests Log10 species richness Post-adelgid, old growth Pre-adelgid, old growth Log10 area

27. Change in the species area relationship over time in second growth forests Log10 species richness Post-adelgid, second growthPre-adelgid, second growth Log10 area

28. Change in the species area relationship over time Log10 species richness Post-adelgid, old growth Pre-adelgid, old growth Post-adelgid, second growthPre-adelgid, second growth Log10 area

29. Parameters of species area relationshipLog S = Z Log A + Log C

30. Summary of species richness and species area relationship results • Species richness decreased slightly at the largest scales in second growth forests. • The primary difference in species area relationships are between second growth and old growth. • There is no difference in species area relationships from before and after the hemlock woolly adelgid. • Time may not be long enough. • In old growth forests, species do not accumulate with area as quickly as in second growth forests.

31. Acknowledgments • Committee • Robert Wyatt • Bob Peet • Peter White • Tom Wentworth • Allan Strand • US Forest Service • National Park Service • Highlands Biological Station • Plant Ecology Lab at UNC • Karen Patterson, Claire Newell, Dan Pittillo,Larissa Knebel, Aaron Cooper