Ecological Forestry Methods in Northern Hardwoods: Predicted Effects on Forest Structure And Production
Event Website
http://www.nafew2009.org/
Start Date
6-23-2009 1:50 PM
End Date
6-23-2009 2:10 PM
Description
Ecological forestry methods that include growing trees to very large diameter, retention of permanent legacy trees, and maintenance of large coarse woody debris (CWD) can have significant beneficial effects on biological diversity and ecosystem processes, but little is known about the potential impacts on timber production rates. To address this need, we used the CANOPY model, a crown-based individual-tree model calibrated with data from mature and old-growth stands, to simulate 7 treatments over a span of 150 years in a second-growth northern hardwood stand. Treatments included an untreated control, standard single-tree selection cutting with maximum retained dbh of 60, 70, or 80 cm, and retention of permanent legacy trees at densities of 7, 15, or 22 per ha. Raising the maximum dbh to 70 or 80 cm reduced net harvestable production by 15-24% but resulted in higher residual stand volumes. Retention of permanent legacy trees in the 60 cm maximum dbh trial reduced production by 9-33% depending on reserve tree density. Reserve trees generally did not increase CWD levels above those obtainable under a no-reserve treatment with a 70 or 80 cm maximum dbh. The different treatments had highly variable effects on the degree to which the size distribution of live trees approached old-growth conditions. Some treatments merely maintained mature forest structure, and two of the reserve-tree treatments had structures that vacillated between mature and borderline old-growth conditions. The 80 cm maximum diameter treatment was the only one that promoted negative exponential size distributions with large trees similar to those in the later stages of old-growth development.
Ecological Forestry Methods in Northern Hardwoods: Predicted Effects on Forest Structure And Production
Ecological forestry methods that include growing trees to very large diameter, retention of permanent legacy trees, and maintenance of large coarse woody debris (CWD) can have significant beneficial effects on biological diversity and ecosystem processes, but little is known about the potential impacts on timber production rates. To address this need, we used the CANOPY model, a crown-based individual-tree model calibrated with data from mature and old-growth stands, to simulate 7 treatments over a span of 150 years in a second-growth northern hardwood stand. Treatments included an untreated control, standard single-tree selection cutting with maximum retained dbh of 60, 70, or 80 cm, and retention of permanent legacy trees at densities of 7, 15, or 22 per ha. Raising the maximum dbh to 70 or 80 cm reduced net harvestable production by 15-24% but resulted in higher residual stand volumes. Retention of permanent legacy trees in the 60 cm maximum dbh trial reduced production by 9-33% depending on reserve tree density. Reserve trees generally did not increase CWD levels above those obtainable under a no-reserve treatment with a 70 or 80 cm maximum dbh. The different treatments had highly variable effects on the degree to which the size distribution of live trees approached old-growth conditions. Some treatments merely maintained mature forest structure, and two of the reserve-tree treatments had structures that vacillated between mature and borderline old-growth conditions. The 80 cm maximum diameter treatment was the only one that promoted negative exponential size distributions with large trees similar to those in the later stages of old-growth development.
https://digitalcommons.usu.edu/nafecology/sessions/silviculture/3