Optimizing the Management of Uneven-aged Forest Stands

1974 ◽  
Vol 4 (3) ◽  
pp. 274-287 ◽  
Author(s):  
Darius M. Adams ◽  
Alan R. Ek

Two perennial problems in the management of uneven-aged forests are considered: (i) determination of the optimal sustainable distribution of trees by diameter class, i.e. stand structure, for a given initial stocking level, and (ii) the optimal cutting schedule for the conversion of an irregular stand to a target structure. It is shown, using examples for northern hardwood stands in Wisconsin, that both problems can be solved via mathematical programming techniques. The programming approaches utilize a set of nonlinear equation models for stand table projections which consider the interdependence of size classes within the stand. To illustrate procedures, optimal stand structures are found for a case where initial stand basal area is constrained to specified levels and the objective is to maximize value growth over the cutting cycle. A conversion cutting schedule is then determined for a case in which the objective is maximization of present worth. It is emphasized that both the optimal distribution and conversion problems can be generalized to consider a broad range of objective functions, lengths of cutting cycle, and constraints on the growing stock.

2021 ◽  
Author(s):  
Mathias Neumann ◽  
Hubert Hasenauer

Abstract Competition for resources (light, water, nutrients, etc.) limits the size and abundance of alive trees a site can support. This carrying capacity determines the potential carbon sequestration in alive trees as well as the maximum growing stock. Lower stocking through thinning can change growth and mortality. We were interested in the relations between stand structure, increment and mortality using a long-unmanaged oak-hornbeam forest near Vienna, Austria, as case study. We expected lower increment for heavy thinned compared to unmanaged stands. We tested the thinning response using three permanent growth plots, whereas two were thinned (50% and 70% basal area removed) and one remained unmanaged. We calculated stand structure (basal area, stem density, diameter distribution) and increment and mortality of single trees. The heavy thinned stand had over ten years similar increment as the moderate thinned and unthinned stands. Basal area of the unthinned stand remained constant and stem density decreased due to competition-related mortality. The studied oak-hornbeam stands responded well even to late and heavy thinning suggesting a broad “plateau” of stocking and increment for these forest types. Lower stem density for thinned stands lead to much larger tree increment of single trees, compared to the unthinned reference. The findings of this study need verification for other soil and climatic conditions.


1994 ◽  
Vol 11 (4) ◽  
pp. 117-123 ◽  
Author(s):  
Blair D. Orr ◽  
David D. Reed ◽  
Glenn D. Mroz

Abstract Beginning in 1958, northern hardwood stands with initial basal areas ranging from 93 to 106 ft²/ac were harvested to residual basal areas of 70, 55, and 40 ft²/ac. Subsequent harvests of the stands over a 32-yr period illustrated potential treatments available to absentee owners of similar stands in small woodlots. In all cases stand quality improved and stand structure became more balanced, with a decrease in the number of trees greater than 20 in. dbh. At discount rates of 2% to 4%, economic returns were greatest for the 70 ft² treatment with a 10 yr cutting cycle. At discount rates of 6, 8, and 10%, the 55 and 40 ft² treatments with 18-and 22-yr cutting cycles, respectively, outperformed the 70 ft² treatment due to greater volume removed during the first (1958) harvest. North. J. Appl. For. 11(4):117-123.


2008 ◽  
Vol 25 (3) ◽  
pp. 133-138 ◽  
Author(s):  
Julia I. Burton ◽  
Eric K. Zenner ◽  
Lee E. Frelich

Abstract Frost cracks are common in northern hardwood stands near their northern range limits. Although they have long been attributed to the regional climate, temperature fluctuations result in surface cracks largely when internal wounds are present. We examined the relationship between the proportion of trees with frost cracks and both tree-level diameter class and stand structural characteristics in primary stands with a history of minimal logging (n = 4) and 67- to 97-year-old second-growth stands subjected to past heavy partial cuts and high grading (n = 8). We hypothesized that frost crack incidence would (1) be greater in the second-growth stands and (2) be associated with differences in structural attributes between the two stand types. High levels of frost cracking in primary stands indicated that cracks are not completely avoidable. However, the proportion of trees with frost cracks was significantly higher in second-growth than primary stands, particularly on small-diameter trees. For example, the odds for frost cracking were 1.66–3.74 times greater in second-growth than in primary stands in the 15-cm diameter class, but were not different in the 45+-cm diameter class. Frost cracking was positively associated with increasing diameter in both stand types. Structural characteristics reflecting tree size, stand basal area, and basal area of hardwoods were positively associated with the proportion of trees with frost cracks in second-growth stands but not in primary stands. Although the basal area of conifers was negatively associated with frost cracking, the effect was likely due to a reduction in hardwood basal area in the vicinity of conifers. We suggest that greater frost crack incidence in second-growth stands is likely a consequence of injuries to residual trees during selective logging.


2012 ◽  
Vol 88 (1) ◽  
pp. 30-39
Author(s):  
François Guillemette ◽  
Marie-Claude Lambert ◽  
Steve Bédard

Sampling design (distribution of plots, plot sizes, and number of sample plots) is an important consideration in planning a field study since it determines the bias and precision of information obtained. In this study, we evaluated the effects of two commonly used sampling designs on the precision of estimates of means related to stand basal area, considered as a whole or by diameter class, and 10-year growth components, in six 2-ha areas located in uneven-aged northern hardwood stands of Quebec managed under selection cutting. The study compares random and systematic sampling designs of one to 10 plots, with plots varying in size from 0.05 ha to 1.25 ha. Increasing the total area sampled (i.e., sampling area) in a stand from 0.05 ha to about 0.25 ha resulted in large precision gains; further increases in sampling area had more limited effects on precision. A sampling area of at least 0.5 ha would be required to obtain a minimally acceptable precision in estimating means of total basal area and 10-year growth components. A much larger sampling area would be required to obtain sufficient precision in estimating mean basal area by diameter class, often required to study stand structure. Precision can also be increased by dividing the sampling area into several smaller plots rather than using a single large plot. We found no clear difference in the results between random and systematic selection approaches.


2005 ◽  
Vol 22 (2) ◽  
pp. 124-131 ◽  
Author(s):  
Thomas J. Seablom ◽  
David D. Reed

Abstract Seven northern hardwood stands were evaluated for damage after mechanized harvesting. Four different harvesting systems were evaluated: harvester and grapple skidder, processor and forwarder, chainsaw and cable skidder, and chainsaw and forwarder. There was not an excessive amount of damage occurring to any of the residual stands, and there was an adequate number of residual trees per acre in all diameter classes to meet residual stand structure goals. The majority of the damage that did occur was to the bole portion of the tree and to the 2–8-in. dbh size classes. There was no strong relationship between amount of damage occurring to residual trees and the number of residual trees per acre, residual basal area per acre, or distance to skid trail. These results indicate that mechanized harvesting can be used in northern hardwoods without causing excessive damage to the residual stand. Recommendations are to continue with current silvicultural prescriptions and to increase forester-operator communication to minimize residual tree damage.North. J. Appl. For. 22(2):124–131.


2007 ◽  
Vol 24 (3) ◽  
pp. 192-196 ◽  
Author(s):  
Laura S. Kenefic ◽  
Ralph D. Nyland

Abstract Although traditional application of the selection system includes a focus on high-value trees that may reduce cavities and snags, few studies have quantified those habitat features in managed uneven-aged stands. We examined the effects of single-tree selection cutting on cavity trees and snags in a northern hardwood stand immediately prior to the second cutting. Marking followed guidelines proposed by Arbogast, C., Jr. (1957. Marking guides for northern hardwoods under selection system. US For. Serv. Res. Pap. 56, Lake States Forest Experiment Station. 20 p.), with the objective of improving stand quality for timber production while maintaining a balanced diameter distribution. The stand contained seven species of cavity trees and snags; sugar maple and American beech were most common, the latter comprising 20% of snags and 26% of cavity trees despite its relatively minor (7%) contribution to stand basal area. We found that 92% of cavity trees were live, underscoring the value of living trees as sources of cavities. Precut cavity tree density (25.2 live cavity trees per hectare) was more than twice that found in other studies of selection stands, although density of snags (11.0 snags per hectare) was comparable or lower. More than 50% of sampled cavity trees were designated for removal in the second selection cut, reducing projected postcut density to 11.0 live cavity trees per hectare, a density similar to that found in other studies. Postcut density of large cavity trees (3.3 live trees >45 cm dbh per hectare) exceeded published guidelines for northern hardwoods (0.25 to 2.5 live cavity trees >45 cm dbh per hectare). We speculate that the relatively high maximum diameter (61 cm dbh) and long cutting cycle (20 years) used to define the target stand structure may have contributed to the number of cavity trees observed. Nevertheless, selection cutting as applied in this study will likely reduce cavity abundance unless retention of trees with decay is explicitly incorporated into the management strategy.


2013 ◽  
Vol 58 (1) ◽  
pp. 12-25
Author(s):  
Silver Sisask

Abstract The effect of drainage in peatland forests has been studied in Estonia but research on bog pine (Pinus sylvestris L.) stands is lacking and mixed opinions on the expediency of amelioration in this site type are found. In order to obtain more information on the post drainage effects, measurements were conducted in a drained oligotrophic bog Scots pine stand (with a relatively thin peat layer) in Järvselja. Relationship between stand characteristics and distance from the drainage ditch was described and measurement data was compared with data that had been collected 59 years earlier in the same stand. Over time the stand structure and productivity had changed. Due to lengthy drainage, increase in several stand characteristics became evident: mean height 84% (8.60 ± 0.39 m), mean DBH 48% (6.55 ± 0.59 cm), basal area 59% (10.6 ± 3.4 m2 ha-1) and growing stock 179% (169 ± 32 m3 ha-1). Growth conditions had improved (site class improvement 1.8 units) and since earlier comparison data was from an already drained stand, actual change in stand characteristics and productivity compared to pre-drained state, has to be even greater. The studied stand is a good example of successful forest drainage in a bog pine forest and these results contribute to a better understanding of post drainage developments in these types of forests


Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1354
Author(s):  
Mathias Neumann ◽  
Hubert Hasenauer

Competition for resources (light, water, nutrients, etc.) limits the size and abundance of live trees a site can support. This carrying capacity determines the potential carbon sequestration in live trees and the maximum growing stock. Lower stocking through thinning can change growth and mortality. We were interested in the relations between stand structure, increment, and mortality using a long-unmanaged oak-hornbeam forest near Vienna, Austria, as a case study. We expected lower increment for heavily thinned compared to unmanaged stands. We tested the thinning response using three permanent growth plots, in which two were thinned (50% and 70% basal area removed) and one remained unmanaged. We calculated stand structure (basal area, stem density, diameter distribution) and increment and mortality of single trees. Over ten years, the heavily thinned stand had a similar increment as that of the moderately thinned and unthinned stands. The basal area of the unthinned stand remained constant and stem density decreased due to competition-related mortality. The studied oak-hornbeam stands responded well even to late and heavy thinning, suggesting a broad “plateau” of stocking and increment for these forest types. Lower stem density for thinned stands led to a much larger tree increment of single trees, compared to the unthinned reference. The findings of this study need verification for other soil and climatic conditions.


Beskydy ◽  
2013 ◽  
Vol 6 (2) ◽  
pp. 99-108
Author(s):  
M. Bátor ◽  
L. Danková

The water-supply storages are important resources of drinking water in some regions of Slovakia, especially in surrounding of Banská Bystrica. Málinec is one of the three storages in this region. In protected zone of this storage are planted Norway spruce (hereinafter „spruce“) stands monocultures because of ensuring required water quality in storage. There are 24 years old spruce stands without admixture of deciduous trees in the upper layer. Understory is formed by blackthorn (PRP 1). On this locality was carried out geometric (schematic) thinning what is not recommended in protected zones because of worse influencing of soil permeability, humus decomposition and open forest edge creating. There was identified one older permanent research plot (PRP) and established one new PRP where was performed own measurements. Into the PRPs there are transekts and remaining area. Acreage of PRP is 0,234 and 0,315 ha. On the whole area were measured tree diameter and assessed tree classes (5 degrees–Polanský 1955). Moreover, on transekts were measured tree and also crown height. Based of measured variables were calculated stand characteristics like slenderness ratio, crown ratio, growing stock and basal area. If it is possible, these were compared with older results. The aim of this work is evaluation of spruce stands structure and their stability after schematic thinning. This kind of silvicultural treatment is absolutely unfit in stands with specific (water-protested) function (Slodičák et al. 2010). These stands are from the perspective of static stability too unfit–basal area and abundance of trees is nearly as in yield tables (Kolektív 1992) but growing stock is much higher and a lot of trees is too slim. The slenderness ratio is from 75 to 90 %. But the crown lenght is quite good with crown ratio 52–64 %. In these ages of stands are crowns reduced too much. Suitable individual thinning has been in these stands neglected (growing stock is higher than normal). There is assumed reduced stand lifetime after schematic thinning. Current stand structure is due to the young age inappropriate.


2020 ◽  
Vol 50 ◽  
Author(s):  
Ferhat Bolat ◽  
Sinan Bulut ◽  
Alkan Günlü ◽  
İlker Ercanlı ◽  
Muammer Şenyurt

Background: The use of satellite imagery to quantify forest metrics has become popular because of the high costs associated with the collection of data in the field.Methods: Multiple linear regression (MLR) and regression kriging (RK) techniques were used for the spatial interpolation of basal area (G) and growing stock volume (GSV) based on Landsat 8 and Sentinel-2. The performance of the models was tested using the repeated k-fold cross-validation method.Results: The prediction accuracy of G and GSV was strongly related to forest vegetation structure and spatial dependency. The nugget value of semivariograms suggested a moderately spatial dependence for both variables (nugget/sill ratio approx. 70%). Landsat 8 and Sentinel-2 based RK explained approximately 52% of the total variance in G and GSV. Root-mean-square errors were 7.84 m2 ha-1 and 49.68 m3 ha-1 for G and GSV, respectively.Conclusions: The diversity of stand structure particularly at the poorer sites was considered the principal factor decreasing the prediction quality of G and GSV by RK.


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