History, Current Status, and Future of Northeastern Forests (with - - PowerPoint PPT Presentation

History, Current Status, and Future of Northeastern Forests

(with particular emphasis on forests of eastern New York)

Charles Canham Cary Institute of Ecosystem Studies Millbrook, NY

Yale University Press Available February 2020

Focusing in on eastern New York: New York FIA statistics by region, 2015

Region Area of forest land (acres) Net Growth (ft3/acre) Removals (ft3/acre) Net change (ft3/acre/yr) Gross Growth (ft3/acre/yr) Ratio of Net Growth / Removals Adirondack Park* 2,780,037 34.8 27.9 6.9 60.2 1.2 Western New York 8,298,735 45.7 17.4 28.3 66.3 2.6 Eastern New York** 5,338,043 43.6 10.2 33.4 68.6 4.3 * Excludes NYS Forest Preserve and other reserved lands

** Eastern region defined as lands south of the Adirondack Park boundary and Delaware and Otsego Counties eastward

Some common misconceptions about the forests of eastern NY (and the rest of the Northeast)..

❖ Very few forests are truly even-aged - “age” as a metric has become meaningless – biomass is far more relevant ❖ The current distribution of forest biomass is strongly skewed towards much lower biomass than would have been present in the presettlement landscape - this is a product of the history of intensive land-use, and is an anomaly in the long-term history of these forests. ❖ Almost none of the forests have reached maximum levels of carbon storage – there is still significant potential for additional carbon sequestration in both live and dead biomass

Great Mountain Forest and a model of forest dynamics

❖ Field research:

▪ Developed new methods to estimate – in the field - all of the critical parameters needed to predict the successional dynamics

• f the 9 tree species at GMF

❖ Modeling:

▪ Developed SORTIE - a spatially explicit, individual-based simulation model to incorporate all

• f the field results

Pacala, S. W., C. D. Canham, J. Saponara, J. A. Silander, Jr., R. K. Kobe, and E. Ribbens. 1996. Forest models defined by field measurements: II. Estimation, error analysis and dynamics. Ecological Monographs 66:1-43.

BASIC NETWORK DESIGN

• Stratified random plot locations
• 1 plot per 6,000 acres of land
• Individual plots recensused ~ every

5-7 years (with a subset of plots sampled each year)

• Data posted and publicly available*

within ~ 1 year after collection

The U.S. Forest Service Forest Inventory and Analysis (FIA) Program

*exact plot locations are confidential, by law…

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The SORTIE-ND software for simulation of forest dynamics…

❖ Individual-based

▪ Simulates the birth, growth, and death of all seedlings, saplings and adult trees, including processes of natural and human disturbance, and effects of processes including pests and pathogens, air pollution, and climate change

❖ Spatially-explicit

▪ The spatial locations of all individuals are tracked, and can be used in processes ranging from seed dispersal to resource competition

❖ Adaptable

▪ Users create and assemble “behaviors” based on available field data

❖ Open-source

▪ The source code and programming guides are available to all users (www.sortie-nd.org) ▪ changes made by any user are incorporated in the base model available to all

A 40 year voyage, and I’m still not sure where the forests are headed … But this I believe:

❖ Forests have enormous demographic inertia – change is slow (in the absence of direct human intervention) ❖ Some changes are inexorable – the broad outlines of succession are predictable, and are defined by shade tolerance ❖ But the notion of “steady state” is largely meaningless (both practically and theoretically). ❖ And forests are “computationally irreducible” – there are no shortcuts to predicting future states – you have to track the entire journey, with all of its twists and turns, from where ever you are now

Currents that keep me on watch…

▪Nature of the presettlement forests and Native American impacts ▪Legacies of European agriculture and forestry ▪Legacies of 20th century fire suppression ▪The fall and rise of white-tailed deer ▪A sea-change in logging ▪Air pollution ▪New passengers – invasive species ▪Even more unwanted passengers – pests and pathogens ▪Climate change

Home port: The ebb and flow of presettlement forests

Hudson Highlands Adirondack Mountains Maenza-Gmelch (1997) Whitehead and Jackson (1990)

Native American impacts

❖Extinction of Pleistocene megafauna (?) ❖Presettlement fire regimes (?) ❖Native American agriculture (?)

Legacies of European agriculture

? Have the forests truly “recovered”?

1700 1800 1850 1900

A branch in the river…

❖Succession on former cultivated fields

▪ Fairly rapid colonization by trees with intermediate-sized wind- dispersed seeds (red maple, white pine, white ash) ▪ Oaks largely absent except along edges (from seed source in hedgerows)

❖Succession on abandoned pastures

▪ Long period of oldfield succession dominated by little bluestem grass ▪ Oaks present throughout because scattered oaks in the pastures served as a local seed source

Legacies of early forestry

Harvest methods may have been low-tech, but forests in the uplands of the northeast were thoroughly exploited…. But with far fewer long-term legacies than from agriculture… Hemlock bark for the tanning industry

Legacies of fire suppression

10 20 30 40 50 60 70 80 Oaks Hickories Hemlock Pine Maples Presettlement Forests Current Forests

Percent Tree Species

❖ Is fire suppression responsible for a reduction in the regional dominance of oak species in many parts of the eastern US? ❖ Has the reduction in the abundance of oaks over the past 100 years fundamentally altered the flammability of these forests?

Composition of the Cary Institute Woods (witness trees in 1750 vs. current composition)

The fall and rise of the white-tailed deer

White-tailed deer (Odocoileus virginanus) Deer exclosure in the Hudson Valley Presettlement density: ~ 10 / sq. mile Current density (northern): ~ 20-40 / sq. mile Current density (southern): > 100 / sq. mile

Impacts on tree regeneration

Densities of seedlings and saplings in 33,310 FIA plots

• 55% of northeastern forests have

seedling and sapling densities in the lowest density classes

• This is close to regeneration failure by

any standard

• Regeneration failure is even more

pronounced in recently logged forests

• Adequate tree regeneration is highest

in far north where severe winters and heavy forest cover limit deer densities…

Garlic mustard Tree of heaven

Unwanted passengers: Invasive plants

The canopy is a zero-sum game, but the understory is not… When does invasion result in displacement of natives?

Allelopathic, and incredibly rapid growth Toxic to endomycorrhizae

Air Pollution...

❖ Acid deposition and soil calcium depletion ❖ Ozone exposure ❖ CO2 fertilization ❖ Nitrogen deposition

Thomas, R. Q., C. D. Canham, K. C. Weathers, and C. L. Goodale. 2010. Increased tree carbon storage in response to nitrogen deposition in the US. Nature Geoscience 3:13-17.

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Effect of nitrogen deposition on forest productivity in the northeastern US At the regional average deposition (~ 7 kg/ha/yr), productivity is enhanced ~ 40% over pre-industrial levels

A sea change in logging

❖Logging accounts for 60% of all adult tree mortality in eastern forests* ❖After many years when net growth far exceeded harvests, harvest rates now equal or exceed net growth in some areas (e.g. Maine) ❖ this is unsustainable by any definition

*For the region from Kentucky and Virginia north to Wisconsin and Maine Canham et al. (2013), Regional variation in forest harvest regimes in the northeastern United States. Ecological Applications 23:515-522.

Public perception: clearcutting is still the dominant forestry

❖ Reality: clearcutting is uncommon except in certain regions and forest types (i.e. spruce/fir forests and increasingly in beech forests).

Frequency distribution of the intensity of harvests in different parts of the 9 northeastern states

Implications of selective logging regimes…

❖ Partial harvesting favors succession towards forests dominated by shade tolerant tree species:

▪ Beech and sugar maple ▪ Eastern hemlock, red spruce, and balsam fir

❖ Regeneration by oaks is still problematic

▪ They need more light ▪ Problems with deer browsing

❖ Emergence of carbon offset markets

▪ Low-grade wood can be worth 2 to 5 times more to a landowner if left in the woods for carbon sequestration ▪ We need a new forestry that embraces the challenge of balancing carbon sequestration with extraction of forest products

Truly destructive passengers: Introduced pests and pathogens

❖ Arguably the most pervasive human impacts on eastern US forests over the past century have been from the introduction of new pests and pathogens… ▪ Chestnut blight ▪ Dutch elm disease ▪ Beech bark disease ▪ Gypsy moth ▪ Hemlock wooly adelgid ▪ Emerald ash borer ▪ Asian longhorned beetle ▪ …?

Heavily diseased and resistant beech trees

New York is ground zero for exotic pests and pathogens

Number of non-native forest pests per county in the US in 2012. (Source: Liebhold et al. 2013)

The tree-SMART Trade Initiative (Gary Lovett, Cary Institute)

Climate change matters, but will take a long time to play out…

• Predicted changes in abundance of the dominant tree species of northern

hardwood forests of the eastern US

• Assuming a 3 degree C increase in temperature over the next 100 years
• With the current regional harvest regime

Aboveground biomass (tons/ha) The first 150 years…

Sugar maple Red maple Beech

The first thousand years…

White pine Tulip poplar

Changes in distribution and abundance: Northern red oak (under current logging regimes, with and without climate change)

Current Distribution 250 Years – No climate 250 years – 3 Degree change warming Aboveground Biomass (mt/ha) Presence (%)

Predicted changes in distribution and abundance: White oak

(under current logging regimes, with and without climate change)

Similar or even more precipitous declines predicted for black oak and chestnut oak Current Distribution 250 Years – No climate 250 years – 3 Degree change warming Aboveground Biomass (mt/ha) Presence (%)

Predicted trends in average biomass, by forest type and region, 2011 - 2160

Red: no climate change Blue: 3o climate change Green: more intensive harvests

What’s behind the increase in landscape average forest biomass?

Current distribution (2011)

• f forest biomass in 5000

randomly selected FIA plots in the northern 4 states (from NY to ME) Predicted distribution in 100 years …maturing of young forests and forests heavily harvested 50 years ago

What are the implications of these predicted increases in forest biomass?

… significant additional potential for carbon sequestration in eastern forests

Hubbard Brook