Spruce Budworm Human Response Cycle: How it shaped everything in Maine forestry for the past 40 years Robert G. Wagner

Transcription

1 Spruce Budworm Human Response Cycle: How it shaped everything in Maine forestry for the past 40 years Robert G. Wagner NERCOFE Workshop University of Maine Orono, ME March 10, 2014

2 Progress of 1970s SBW Outbreak in Maine

3 Spruce Budworm Life Cycle Choristoneura fumiferana (Clemens)

4 SBW Fir-Spruce Stand Development Life Cycle (ala Baskerville 1975) advance seedlings not shown 80-yr old stand mostly killed 40-yr old stand heavily thinned

5 SBW Human Competition Cycle?? SBW is a natural predator of the Acadian Spruce-Fir Forest (enjoy all the leafy fir and spruce flesh the forest can yield) Humans are recent predators of the Acadian Spruce-Fir Forest (enjoy all the woody flesh the forest can yield) Figure 1: Population cycles in a Swedish forest community The top figure (a) shows changes in population size for voles and small game. The striped arrows indicate years in which voles consumed tree bark as a marginal food. The bottom figure (b) illustrates how predator populations change in relation to prey abundance. Predators of the same prey are competitors and therefore interact with the population changes of the other Now that humans occupy the Acadian Forest, is there a human- SBW competitive interaction?

6 Spruce Budworm Human Behavioral Response Cycle?? ( ) Spruce Budworm Dead forest Clearcut salvage logging More mills All partial cutting Federal Protection More lynx Worry about future softwood supply Forest Practices Act More hare Insecticide spraying People protest clearcutting PCT Thick conifer stands Herbicide spraying

7 The spruce budworm killed millions of acres of forest stands from 1975 to 1985

8 Between 20 and 25 million cords of spruce and fir were killed between 1975 and 1988 as a result of the spruce budworm epidemic. (Assessment of Maine s Wood Supply, Maine Forest Service, November 1993) Current annual harvest of spruce-fir is about 1.5 million cords (13-16 year supply was lost)

9 View from top of Mt. Katahdin in 1980 Color Photo from Knife Edge Trail by Dr. David Field 1980

10 And we sprayed millions of acres with insecticides from 1972 to 1985

11 Area Treated (million acres) Area Sprayed With Insecticides During 1970s-80s SBW Outbreak in Maine

12 And Maine landowners salvage logged (clearcut) the dead fir and spruce on millions of acres in the 1970s and 1980s

13 Rumford paper mill And Mill capacity was expanded to process the SBWkilled forests

14 Maine Wood Processing Facilities Biomass Energy Plants Pulp & Paper Mills Sawmills

15 Which led to more clearcutting And the mill owners became worried about a future shortage of spruce and fir to feed their mills

16 Which led to the the first wood supply forecast for Maine using the first computer model 1983 Sewall Report First official wood supply forecast for Maine Done to estimate need for permanent protection zone Used the Green Woods model which incorporated budworm dynamics into harvest scheduling decisions Used newly acquired 1982 FIA data before it was published

17 1983 Sewall Report Predicted major declines in spruce-fir inventory, regardless of protection level Everyone was depressed!

18 Most of those clearcuts came back to shrubs and low-value hardwoods that suppressed the regenerating balsam fir and red spruce

19 So, the forest landowners sprayed herbicides on the clearcuts to release young spruce and fir

20 Area Sprayed With Herbicides After the Budworm Land area (000 acres) Forestland Area Treated With Herbicides and PCT in Maine from

21 And the softwoods became too dense in many places

22 So, many of the young stands were precommercially thinned

23 Area Precommercially Thinned After the Budworm 30 Forestland Area Precommercially Thinned in Maine from Land area (000 acres)

24 Total Area Sprayed and Thinned in Maine After the Budworm Land area (000 acres) Cumulative Forestland Area Treated With Herbicides and PCT in Maine Herbicide PCT

25 40-year Outcomes in Austin Pond Study Merchantable Softwood Volume 286 ft 3 /acre (20 m 3 /ha) No Treatment Basal Area 33% 18% 27% 18% 4% Balsam fir Spruce Aspen Red maple Other 20% 1,072 ft 3 /acre (75 m 3 /ha) Herbicide Only 6% 15% 43% 3.8X Commercial thinning anyone? 4% 12% 16% 2,001 ft 3 /acre (140 m 3 /ha) 7.0X Herbicide + PCT 7% 55% 22% Bataineh et al CJFR 43:

26 And the snowshoe hare (Lepus americanus) loved the thick, conifer stands and reproduced a lot

27 Relationship of Hare Density and Density of Conifer Saplings Hares/ha ,000 10,000 15,000 20,000 25,000 30,000 Conifer stems/ha Median conifer stem density in regenerating conifers = 11,850 versus 3,350 in partial harvests Source: Harrison lab, UMaine, 2010

28 Hare Habitat Change in N. Maine = 4.3 to 4.8 x increase 30,000 25,000 20,000 Acres 15,000 10,000 5, Year Source: Harrison lab, UMaine, 2010

29 Which the Canada lynx (Lynx canadensis) liked a lot, and they also multiplied

30 And so did most of the other major predators of the Maine forest, who also like to eat hare

31 Relation between Landscape-level Hare Density and Lynx Occurrence Probability of lynx occurrence Lynx have highest probability of occurrence if there is at least 1 hare per ha Hare density (#/ha) Source: Harrison lab, UMaine, 2010

32 Densities of Snowshoe Hares by Forest Types During High Hare Period ( ) Forest types Hares/ha Years Regenerating clearcuts (4 studies) Regenerating clearcuts + PCT Shelterwood and Overstory Removal Selection Harvests (established) Budworm-kill conifer Mature mixed deciduous/coniferous Mature coniferous Mature deciduous Selection Harvests (recent)* From: Fuller & Harrison JWM 2005, Homyack et al. JWM 2007, Robinson And no good deed went unpunished

33 In 2005 northern Maine was designated as Critical-Habitat by the USFWS In March 2000, the USFWS listed Canada lynx as threatened in the lower 48 states Maine has largest lynx population in lower 48 states

34 Despite the fact that hare, lynx, and other predators apparently liked the clearcuts, many humans thought the clearcuts were ugly and an ecological disaster Which led to: Lots of political pressure Passage of the Forest Practices Act (1989) 3 voter referenda to ban clearcutting (1996, 1997, 2000)

35 The 1989 Maine FPA defined and regulated all clearcuts in the state 1. Clear-cut. "Clear-cut" means any timber harvesting on a forested site greater than 5 acres in size that results in a residual basal area of trees over 4 1/2 inches in diameter measured at 4 1/2 feet above the ground of less than 30 square feet per acre, unless, after harvesting, the site has a well-distributed stand of acceptable growing stock, as defined by rule, of at least 3 feet in height for softwood trees and 5 feet in height for hardwood trees that meets the regeneration standards defined under section 8869, subsection No clearcut shall be larger than 250 acres in size. a) Category 1 clearcut is > 5 acres and 20 acres. b) Category 2 clearcut is >20 acres and 75 acres. c) Category 3 clearcut is >75 acres and 250 acres. 3. All clearcuts must have a separation zone of at least 250 feet from any other clearcut

36 And patterns of forest harvesting changed quickly and drastically across the land

37 Maine Harvest Area By Method ( ) Passage of Maine FPA Land area (x1000 acres) End of SBW outbreak Referendum #1 Referendum #2 Referendum #3 Clearcutting Partial cutting TOTAL Source: Maine Forest Service, Silvicultural Activities Reports

38 Maine Harvest Area vs. Wood Volume Harvested ( ) Area harvested (thousand acres) Passage of the Maine FPA And we doubled the annual harvest footprint to obtain the same amount of wood Harvested area Wood Volume Wood Volume (million cords) Year Source: Maine Forest Service, Silvicultural Activities and Wood Processor Reports

39 And the wave of partial cutting could be seen from space, and substantially changed the composition, structure, and productivity of the forest

40 And investments in silviculture declined Area of Tree Planting, Herbicide Application, and PCT in Maine from Land area (x1000 acres) Herbicide PCT Planting

41 And the FPA separation zones made forest management more difficult Increases stand fragmentation Longer forwarder trails Higher management and operational costs Forces suboptimal silviculture in some places Complicates forest-level planning Increases wood costs May be a substantial limitation in future SBW salvage logging

42 And all of the partially harvested stands supported fewer hares and became poorer lynx habitat

43 Lynx Habitat Change on 1.6 Million Acres of Northern Maine Forestland Source: Simons, E.M UMaine PhD Thesis.

44 Is there a SBW Human Behavioral Response Cycle? Spruce Budworm Dead forest Clearcut salvage logging More mills All partial cutting Federal Protection More lynx Worry about future softwood supply Forest Practices Act More hare Insecticide spraying People protest clearcutting PCT Thick conifer stands Herbicide spraying

45 Quebec 2012 SBW Outbreak Map And they re back The cycle begins again!

46 July North of Forestville, QC. 90+% of the fir had damage. Some of the spruce was damaged. The photos don't show it, but this is the condition affecting every stand on every hill and valley in the region. Currently there are 2.5 million ha in Quebec in a similar condition. Only a stand sprayed twice with Btk was green (not shown). Quebec only sprayed 120,000 ha this year. Ked Coffin, JD Irving

47 Thank You!

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49 Thank You!

50 Will the SBW human response life cycle be the same next time around? Will we do better?

51 Thank You!