Maine Adaptive Silviculture Network
The late 1970s and early 80s
In the late 1970s and early 80s there was an outbreak of spruce budworm that killed millions of trees in the state of Maine and Canada. The subsequent salvage logging and regeneration of the spruce/fir stands has shaped the way we manage our forests and the challenges that we face today as an industry.
2000
In the early 2000s many of the stands that had been salvage logged were nearing the age of operability and so the Cooperative Forestry Research Unit (CFRU) formed the Commercial Thinning Research Network (CTRN) to better understand how spruce/fir stands reacted to different thinning regimes.
2016
The CTRN was successful at understanding how thinning regimes could affect stand and individual tree growth but the small scale (approximately 1/5th of an acre) of the research plots made it difficult to make inferences at an operational scale (20+ acres). In 2016, Maine Adaptive Silviculture Network (MASN) was created to provide a platform to answer these operational scale questions.
Present
Maine hosts a wide variety of landscapes, forest types and underlying site characteristics which play a large role in how our forests grow and respond to management. In order to capture this variability, site and forest characteristics such as hardwood/softwood composition and Biomass Growth Index, or the amount of biomass that a particular site could theoretically hold, were used for site selection.
After a site is selected, a variety of management options are discussed between the CFRU staff and landowner foresters. Silvicultural prescriptions are developed to satisfy the landowners needs and questions as well as replicating treatments across the network, ensuring that this study will provide an opportunity for researchers to answer questions for decades to come.
Original goals of the study include:
- Comparing outcomes of different silvicultural treatments
- Quantifying productivity and costs of multiple harvesting methods
- Informing and improving growth and yield models
- Validating remotely sensed data for forest inventory and wildlife habitat
- Quantifying effects of forest management on wildlife
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1
AFM Grand Falls
4 treatments installed in 2017.
Partial harvest (PH_Exemplary): a thinning from below and harvest of mature trees (Photo 1)
Partial harvest (PH_FPA): a thinning from above focused on high value trees (Photo 2)
Clearcut with residuals (CC_FPA): commercial clearcut with residual volumes left to satisfy Maine FPA standards (not pictured)
Clearcut (CC_Exemplary): all stems removed (Photo 3)
Delayed Harvest: a control block with no harvesting activity (Photo 4)
Note: All images taken 5 years post harvest
2
AMC Brownsville
Planned installation of 4 treatments in 2024.
American beech cleaning: all beech stems will be severed below the lowest live branch to reduce competition for more desirable species (Photo 1)
Hardwood PCT: hardwood stems will be thinned to increase growing space and reduce competition (Photo 2)
Clearcut: all stems will be severed to promote regeneration (Photo 3)
Hardwood crop tree release: crop trees will be identified and competing trees will be removed to increase the future value of the crop trees (Photo 4)
Delayed Harvest: a control block where no treatment occurs (Photo 5)
Note: all photos were taken in the summer of 2023, preharvest
3
Baskahegan Brookton
Planned installation of 3 treatments in 2024.
Chemical crop tree (TBD2): herbicide application to reduce competition for identified crop trees (Photo 1)
Mechanical crop tree (TBD3): crop trees will be identified and competing trees will be removed to increase the future value of the crop trees (Photo 2)
American beech cleaning (TBD4): all beech stems will be severed below the lowest live branch to reduce competition for more desirable species (Photo 3)
Delayed Harvest: a control block with no harvesting activity (Photo 4)
Note: all photos were taken in the fall of 2023, preharvest
4
CLWH Oxbow
4 Treatments installed in 2019.
Shelterwood removal (SWR): Removal of merchantable overstory trees to release advance, pole-sized regeneration. Spruce >12" with 1/3 or more live crown, Eastern white pine and Northern white-cedar were retained. (Photo 1)
Silvicultural Clearcut (SCC): Removal of all stems. (Photo 2)
Variable Group Entries (GPE): Create small 1/4 to 1/2 acre openings in areas that have higher component of balsam fir of poor quality. (Photo 3)
Early Commercial Thinning (ECT): Reduction of basal area by no more than 30-40%. Retain all crop trees (35% live crown, no major external defect). Target species for harvest in the following order: balsam fir, aspen, white birch, red maple, yellow birch and red spruce. (Photo 4)
Delayed Harvest: a control block with no harvesting activity (Photo 5)
Note: All photos were taken in summer 2023, 4 years postharvest.
5
JDI Saul's Brook
6 treatments installed in 2018.
Clearcut for hardwood (CC_Hardwood): Removal of all merchantable stems. Regeneration flattened to prepare site for hardwood release.
Clearcut for softwood (CC_Softwood): Removal of all merchantable stems. Regeneration flattened for site preparation and planting. (Photo 1)
Overstory Removal (Overstory_Removal): Removal of all merchantable stems that are overtopping regeneration. Future yellow birch and sugar maple sawlogs 8" DBH or less will be left.
Partial harvest mechanical crop tree: Leave quality growing stock trees across all size classes (regeneration, poles, immature & mature). All stems left to be protected. Leave spruce under 8" DBH and with 40% or greater live crown. Residual stems must be able to remain in the stand for 15-20 years.
Partial harvest chemical crop tree: Leave quality growing stock trees across all size classes (regeneration, poles, immature & mature). All stems left to be protected. Leave spruce under 8" DBH and with 40% or greater live crown. Residual stems must be able to remain in the stand for 15-20 years.
Partial harvest diameter limit (PH_Diameter_Limit): Removal of high value stems across block. Residual species are protected.
Delayed Harvest: a control block with no harvesting activity.
Note: Photo was taken in 2022, 4 years postharvest.
6
SILC Nashville Plantation
5 treatments installed in 2020 and 2022.
Clearcut (Clearcut_no_burn): Removal of all stems. (Photo 1)
Clearcut and burn (Clearcut_burn): The clearcut block was split in half 2 years after treatment and a prescribed fire was implemented on one half as a means of site preparation. (Not pictured here)
Improvement cut (Improvement_Cut): Retain yellow birch, sugar maple and red spruce for seed trees. Retain large Eastern hemlock to meet biodiversity and C storage objectives. Other objectives included maintaining a multi-aged structure, promoting species predicted to be well-adapted to future climate conditions (e.g. yellow birch, poplar and maples), and regenerating yellow birch in canopy gaps during future harvests. (Photo 2)
Overstory Removal (Shelterwood_Removal): (Photo 4)
Shelterwood with reserves (Shelterwood_with_Reserves): (Photo 5)
Delayed Harvest: a control block with no harvesting activity. (Photo 6)
Note: Photos were taken in 2022, 2 years postharvest.
7
SILC T13R15
4 treatments installed in 2018.
Clearcut (CC_Exemplary): Remove all stems.
Overstory Removal (CC_FPA): Removal of all merchantable stems that are overtopping regeneration. Future yellow birch and sugar maple sawlogs 8" DBH or less will be left.
Partial Harvest Crop Tree Release (PH_Exemplary): Leave quality growing stock trees across all size classes (regeneration, poles, immature & mature). All stems left to be protected. Leave spruce under 8" DBH and with 40% or greater live crown. Residual stems must be able to remain in the stand for 15-20 years.
Partial Harvest Diameter Limit (PH_FPA): Removal of high value stems across block. Residual species are protected.
Delayed Harvest: a control block with no harvesting activity.
8
Wagner Stetsontown
4 treatments installed in 2018.
Clearcut: Removal of all stems.
Partial Harvest Crop Tree (CropTree_Selection): Removal of large, poorly formed hardwoods and large spruce.
Diameter Limit (High_Grade): Removal of all trees larger than pole size.
Overstory removal (Overstory): Removal of all merchantable trees leaving as many pole sized trees as possible.
Delayed Harvest: a control block with no harvesting activity.
9
Weyerhaeuser Mayfield
4 treatments installed in 2021.
Clearcut with Residuals (CC_W_Residuals): Removal of all stems while protecting regeneration where possible. (Photo 1)
Clearcut (Clean_CC): Removal of all stems to promote regeneration. (Photo 2)
Hardwood Pre-commercial Thinning (Hardwood_PCT): Thinning of understory to reduce competition. Prioritization: Yellow birch, sugar maple, white ash, red maple, white birch, aspen, smooth barked beech. Leave all softwood and overstory trees. (Photo 3)
Overstory Removal (OSR): Removal of all merchantable stems greater than 4" DBH. Leave at least 450 TPA of regeneration. Retain all hardwoods greater than 25" DBH. (Not pictured here)
Delayed Harvest: a control block with no harvesting activity. (Photo 4)
Note: Photos were taken in 2022 and 2023 for the Hardwood PCT, all 1 year postharvest.
10
Weyerhaeuser Thorndike
5 treatments installed in 2019.
Projects and Publications Using MASN:
- Joshua J. Puhlick, Aaron R. Weiskittel, Ivan J. Fernandez, Kevin A. Solarik & Darren J. H. Sleep (2022) Evaluation of projected carbon accumulation after implementing different forest management treatments in mixed-species stands in northern Maine, Carbon Management,13:1, 190-204, DOI: 10.1080/17583004.2022.2063761
