Dynamics of the diameter distribution after selection cutting in uneven- and even-aged northern hardwood stands: a long-term evaluation

2019 ◽  
Vol 49 (12) ◽  
pp. 1525-1539 ◽  
Author(s):  
Sarita Bassil ◽  
Ralph D. Nyland ◽  
Christel C. Kern ◽  
Laura S. Kenefic

Selection cutting is defined as a tool for uneven-aged silviculture. Dependence on diameter distribution by forestry practitioners for identifying stand conditions has led to misuse of selection-like cuttings in even-aged northern hardwood stands. Our study used several long-term data sets to investigate the temporal stability in numbers of trees per diameter class in uneven-aged northern hardwood stands treated with single-tree selection and in 45-year-old second-growth stands treated with selection-like cuttings. We analyzed data from New York, Michigan, and Wisconsin to determine changes through time in number of trees across 2.5 cm diameter classes, shifts in the shape and scale of the three-parameter Weibull function used to describe the diameter distributions, and dynamics of associated stand attributes. Findings showed that single-tree selection cutting created and sustained stable diameter distributions and uniformity of conditions through consecutive entries in uneven-aged stands. By contrast, these characteristics varied through time in the second-growth stands that had been treated with selection-like cuttings. Analysis also showed that the Weibull shape and scale parameters for stands under selection system migrated towards those of the recommended target diameter distribution in the uneven-aged stands. These parameters diverged from the target with repeated use of selection-like cuttings in the second-growth even-aged stands.

1989 ◽  
Vol 6 (1) ◽  
pp. 34-36 ◽  
Author(s):  
Robert H. Jones ◽  
Ralph D. Nyland ◽  
Dudley J. Raynal

Abstract Root sprout and seedling regeneration of American beech was sampled in two maple-dominated northern hardwood stands 13-14 years after single-tree selection cutting. The largest stems had been advance regeneration, and seedlings comprised a substantial and well-distributed portion of these. Among stems established after the cut, root sprouts outnumbered seedlings. Total beech regeneration abundance was correlated with basal area of overstory beech. For long-term beech control, it may be useful to reduce beech seedling populations before selection cutting, and to cut large diameter beech trees. North. J. Appl. For. 6:34-36, March 1989.


2020 ◽  
Author(s):  
Alexander C Helman ◽  
Matthew C Kelly ◽  
Mark D Rouleau ◽  
Yvette L Dickinson

Abstract Managing northern hardwood forests using high-frequency, low-intensity regimes, such as single-tree selection, favors shade-tolerant species and can reduce tree species diversity. Management decisions among family forest owners (FFO) can collectively affect species and structural diversity within northern hardwood forests at regional scales. We surveyed FFOs in the Western Upper Peninsula of Michigan to understand likely future use of three silvicultural treatments—single-tree selection, shelterwood, and clearcut. Our results indicate that FFOs were most likely to implement single-tree selection and least likely to implement clearcut within the next 10 years. According to logistic regression, prior use of a treatment and perceived financial benefits significantly increased the odds for likely use for all three treatments. Having received professional forestry assistance increased likely use of single-tree selection but decreased likely use of shelterwood. We discuss these results within the context of species diversity among northern hardwood forests throughout the region.


2020 ◽  
Author(s):  
Adrian Norman Goodwin

Abstract Diameter distribution models based on probability density functions are integral to many forest growth and yield systems, where they are used to estimate product volumes within diameter classes. The three-parameter Weibull function with a constrained nonnegative lower bound is commonly used because of its flexibility and ease of fitting. This study compared Weibull and reverse Weibull functions with and without a lower bound constraint and left-hand truncation, across three large unthinned plantation cohorts in which 81% of plots had negatively skewed diameter distributions. Near-optimal lower bounds for the unconstrained Weibull function were negative for negatively skewed data, and the left-truncated Weibull using these bounds was 14.2% more accurate than the constrained Weibull, based on the Kolmogorov-Smirnov statistic. The truncated reverse Weibull fit dominant tree distributions 23.7% more accurately than the constrained Weibull, based on a mean absolute difference statistic. This work indicates that a blind spot may have developed in plantation growth modeling systems deploying constrained Weibull functions, and that left-truncation of unconstrained functions could substantially improve model accuracy for negatively skewed distributions.


2014 ◽  
Vol 90 (04) ◽  
pp. 503-515 ◽  
Author(s):  
Mathieu Fortin ◽  
Stéphane Tremblay ◽  
Robert Schneider

In this study, we addressed the issue of model evaluation when long-term monitoring data are unavailable or inappropriate. More specifically, we fitted a single tree-based growth model for pure even-aged balsam fir stands and we compared stochastic predictions with an existing maximum size–density relationship (MSDR). Growth trajectories for plots of different initial densities and diameter distributions were simulated over a 70-year period using 500 realizations for each combination of initial density-diameter distribution. Long-term predictions were consistent with the existing MSDR. The model properly reproduced the senescence phase in which the trajectories diverge from the MSDR. This phase was initiated when the average tree volume reached 0.2-0.3 m3 per tree, which roughly corresponded to a DBH (diameter at breast height, 1.3 m from the ground) between 19 and 23 cm. Although it cannot be generalized, our case study shows that a simple single tree-based growth model with a distance-independent competition index and no stand density index can reproduce an existing MSDR. The match between long-term predictions and an existing MSDR strengthens the confidence in the biological behaviour of the model.


2003 ◽  
Vol 79 (5) ◽  
pp. 898-905 ◽  
Author(s):  
Steve Bédard ◽  
Zoran Majcen

Eight experimental blocks were established in the southern part of Québec to determine the growth response of sugar maple (Acer saccharum) dominated stands after single tree selection cutting. Each block contained eight control plots (no cut) and eight cut plots. The intensity of removal varied between 21% and 32% and residual basal area was between 18.2 and 21 m2/ha. Ten year net annual basal area growth rates in cut plots (0.35 ± 0.04 m2/ha) were significantly higher (p = 0.0022) than in control plots (0.14 ± 0.06 m2/ha). The treatment particularly favoured diameter growth of stems between 10 and 30 cm in dbh, whose crowns were released by removing neighbouring trees. These results show that if the same net growth rate is maintained in the next decade most of the cut plots will reach their pre-cut basal area in about 20 years after cutting. Key words: northern hardwoods, selection cutting, uneven aged silviculture, basal area growth, diameter growth


Sign in / Sign up

Export Citation Format

Share Document