Approximating natural landscape pattern using aggregated harvest

2007 ◽  
Vol 37 (10) ◽  
pp. 1846-1853 ◽  
Author(s):  
Matthew Carlson ◽  
Werner A. Kurz

Successful implementation of the natural disturbance model for timber harvest is hindered by the lack of strategies to approximate landscape fire pattern. In the forests of Alberta, Canada, the fire regime is dominated by large fires that create large regions of same-aged forest. Current forestry practices disperse harvest blocks across the landscape, causing increased fragmentation as compared with fire. Aggregating harvest blocks is one potential strategy to improve approximation of natural landscape pattern. We used a simulation approach to compare landscape pattern created by aggregated harvest strategies, the current dispersed harvest approach, and the natural disturbance regime for a 270 000 ha forest landscape in northeastern Alberta. Compared with dispersed harvest, aggregated strategies increased compatibility with natural landscape pattern by reducing fragmentation. Capacity to aggregate harvest declined when the constraint of maintaining a constant proportion of deciduous to coniferous harvest was included. We conclude that aggregated harvest can improve implementation of the natural disturbance model by bringing several landscape metrics closer to the conditions that fall within the natural range of variability. Aggregated harvest alone, however, performed poorly at maintaining interior old forest, emphasizing that an explicit old-forest strategy is also required.

Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 491 ◽  
Author(s):  
Matthew Russell ◽  
Stephanie Patton ◽  
David Wilson ◽  
Grant Domke ◽  
Katie Frerker

The amount of biomass stored in forest ecosystems is a result of past natural disturbances, forest management activities, and current structure and composition such as age class distributions. Although natural disturbances are projected to increase in their frequency and severity on a global scale in the future, forest management and timber harvesting decisions continue to be made at local scales, e.g., the ownership or stand level. This study simulated potential changes in natural disturbance regimes and their interaction with timber harvest goals across the Superior National Forest (SNF) in northeastern Minnesota, USA. Forest biomass stocks and stock changes were simulated for 120 years under three natural disturbance and four harvest scenarios. A volume control approach was used to estimate biomass availability across the SNF and a smaller project area within the SNF (Jeanette Project Area; JPA). Results indicate that under current harvest rates and assuming disturbances were twice that of normal levels resulted in reductions of 2.62 to 10.38% of forest biomass across the four primary forest types in the SNF and JPA, respectively. Under this scenario, total biomass stocks remained consistent after 50 years at current and 50% disturbance rates, but biomass continued to decrease under a 200%-disturbance scenario through 120 years. In comparison, scenarios that assumed both harvest and disturbance were twice that of normal levels and resulted in reductions ranging from 14.18 to 29.85% of forest biomass. These results suggest that both natural disturbances and timber harvesting should be considered to understand their impacts to future forest structure and composition. The implications from simulations like these can provide managers with strategic approaches to determine the economic and ecological outcomes associated with timber harvesting and disturbances.


2016 ◽  
Vol 24 (3) ◽  
pp. 233-243 ◽  
Author(s):  
Chris Stockdale ◽  
Mike Flannigan ◽  
Ellen Macdonald

As our view of disturbances such as wildfire has shifted from prevention to recognizing their ecological necessity, so too forest management has evolved from timber-focused even-aged management to more holistic paradigms like ecosystem-based management. Emulation of natural disturbance (END) is a variant of ecosystem management that recognizes the importance of disturbance for maintaining ecological integrity. For END to be a successful model for forest management we need to describe disturbance regimes and implement management actions that emulate them, in turn achieving our objectives for forest structure and function. We review the different components of fire regimes (cause, frequency, extent, timing, and magnitude), we describe low-, mixed-, and high-severity fire regimes, and we discuss key issues related to describing these regimes. When characterizing fire regimes, different methods and spatial and temporal extents result in wide variation of estimates for different fire regime components. Comparing studies is difficult as few measure the same components; some methods are based on the assumption of a high-severity fire regime and are not suited to detecting mixed- or low-severity regimes, which are critical to END management, as this would affect retention in harvested areas. We outline some difficulties with using fire regimes as coarse filters for forest management, including (i) not fully understanding the interactions between fire and other disturbance agents, (ii) assuming that fire is strictly an exogenous disturbance agent that exerts top-down control of forest structure while ignoring numerous endogenous and bottom-up feedbacks on fire effects, and (iii) assuming by only replicating natural disturbance patterns we preserve ecological processes and vital ecosystem components. Even with a good understanding of a fire regime, we would still be challenged with choosing the temporal and spatial scope for the disturbance regime we are trying to emulate. We cannot yet define forest conditions that will arise from variations in disturbance regime; this then limits our ability to implement management actions that will achieve those conditions. We end by highlighting some important knowledge gaps about fire regimes and how the END model could be strengthened to achieve a more sustainable form of forest management.


2002 ◽  
Vol 78 (5) ◽  
pp. 665-671 ◽  
Author(s):  
P Lefort ◽  
B Harvey ◽  
J Parton ◽  
G KM Smith

A review of the scientific literature relevant to the Claybelt region was undertaken under the initiative of Lake Abitibi Model Forest (LAMF) and in collaboration with the Canadian Forest Service, the Ontario and Quebec Ministries of Natural Resources and the NSERC-UQAT-UQAM (Natural Sciences and Engineering Research Council – Université du Québec en Abitibi-Témiscamingue – Université du Québec à Montréal) Industrial Chair in Sustainable forest Management. The objective was to synthesize this information in order to develop better forestry practices and identify knowledge and research gaps. Forestry-related knowledge was gathered on six broad topics: i) natural disturbances, ii) forest ecosystems, iii) past and present forest practices, iv) biological diversity, v) forest management and vi) examples of current applications of natural disturbance-based forest management. The work allowed us to synthesize a large body of knowledge into one publication that will be a useful reference for foresters in both provinces. Key words: biodiversity, Claybelt, even-aged/uneven-aged forests, fire, silvicultural practices


2010 ◽  
Vol 95 (1-2) ◽  
pp. 61-67 ◽  
Author(s):  
Weizhong Su ◽  
Chaolin Gu ◽  
Guishan Yang ◽  
Shuang Chen ◽  
Feng Zhen

1993 ◽  
Vol 17 (3) ◽  
pp. 139-145 ◽  
Author(s):  
Ronald E. Masters ◽  
David M. Engle ◽  
Ray Robinson

Abstract Soil chemical properties on mountainous terrain in oak-pine forests of southeastern Oklahoma changed following timber harvest and prescribed fire. Differences were related to residual stand characteristic, prescribed fire regimen, and vegetation change following site perturbation. Available NO3-N, Ca, and P significantly increased on harvested and burned sites, and on clearcut, windrowed, and summer burned sites compared to untreated sites. Nitrate levels were statistically unrelated to a 2,690% increase (7 to 190 lb/ac) in legume standing crop across site treatments. Nitrate levels were low, and these sites may be nitrogen limited. No increase was found in soil pH. Effects of burning harvested sites on most soil chemical properties generally persisted less than 2 yr. A timber harvest-fire interaction on levels of available K and Mg was evident 4 yr posttreatment. Timber harvest, periodic prescribed fire, and subsequent plant succession redirected nutrient cycling pathways and enhanced soil nutrient levels. Enhanced nutrient regimes are ecologically advantageous for stand reinitiation and recovery following site perturbation or natural disturbance. South. J. Appl. For. 17(3):139-145.


2005 ◽  
Vol 64 (1) ◽  
pp. 44-56 ◽  
Author(s):  
Christy E. Briles ◽  
Cathy Whitlock ◽  
Patrick J. Bartlein

AbstractThe forests of the Siskiyou Mountains are among the most diverse in North America, yet the long-term relationship among climate, diversity, and natural disturbance is not well known. Pollen, plant macrofossils, and high-resolution charcoal data from Bolan Lake, Oregon, were analyzed to reconstruct a 17,000-yr-long environmental history of high-elevation forests in the region. In the late-glacial period, the presence of a subalpine parkland of Artemisia, Poaceae, Pinus, and Tsuga with infrequent fires suggests cool dry conditions. After 14,500 cal yr B.P., a closed forest of Abies, Pseudotsuga, Tsuga, and Alnus rubra with more frequent fires developed which indicates more mesic conditions than before. An open woodland of Pinus, Quercus, and Cupressaceae, with higher fire activity than before, characterized the early Holocene and implies warmer and drier conditions than at present. In the late Holocene, Abies and Picea were more prevalent in the forest, suggesting a return to cool wet conditions, although fire-episode frequency remained relatively high. The modern forest of Abies and Pseudotsuga and the present-day fire regime developed ca. 2100 cal yr B.P. and indicates that conditions had become slightly drier than before. Sub-millennial-scale fluctuations in vegetation and fire activity suggest climatic variations during the Younger Dryas interval and within the early Holocene period. The timing of vegetation changes in the Bolan Lake record is similar to that of other sites in the Pacific Northwest and Klamath region, and indicates that local vegetation communities were responding to regional-scale climate changes. The record implies that climate-driven millennial- to centennial-scale vegetation and fire change should be considered when explaining the high floristic diversity observed at present in the Siskiyou Mountains.


2011 ◽  
Vol 368-373 ◽  
pp. 1724-1731
Author(s):  
Ming Hua Huang ◽  
Yang Wang ◽  
Xiao Nan Shi

The author’s observation on the new urban form of Ankang city grounded on the landscape pattern by analyzing and evaluating the present conditions of land resources, historic cultural attractions, and natural landscape from ecological perspective, finding out the problems in the current construction of urban landscape environment with consideration on local special landscape theme. Besides, the authors emphasized and constructed the landscape patterns at master planning level by layout of city green corridor, preservation of the wetland as the urban corn and improvement of the urban green space system in combination of history, culture and natural environment, urban space and urban spirit, as well as history and future construction.


2007 ◽  
Vol 83 (1) ◽  
pp. 72-83 ◽  
Author(s):  
Annie Belleau ◽  
Yves Bergeron ◽  
Alain Leduc ◽  
Sylvie Gauthier ◽  
Andrew Fall

It is now recognized that in the Canadian boreal forest, timber harvesting activities have replaced wildfires as the main stand-replacing disturbance. Differences in landscape patterns derived from these two sources of disturbance have, however, raised concerns that the way forest harvesting has been dispersed is potentially shifting patterns away from the natural range. In the context of natural disturbance-based management, we used a spatially explicit model designed to capture general fire regimes in order to quantify temporal variability associated with regenerating areas (burnt areas of 25 years or younger), and to develop strategic objectives for harvest agglomeration sizes and dispersion. We first evaluated temporal variability in the proportion of stands younger than 100 years (assumed to be even-aged stands) for various fire regimes (seven fire cycles: 50 to 400 years, and three mean fires sizes: 3000, 15 000 and 60 000 ha). Secondly, we quantified the size distribution and dispersion of regenerating areas for each fire regime. As expected by theoretical fire frequencies and size distributions, the importance of even-aged stands at the forest management unit level was found to decrease with longer fire cycles. However, the temporal variability associated with these proportions is shown to increase with mean fire size. It was also observed that the size distribution and dispersion of regenerating areas was primarily influenced by mean fire size. Based on these observations, natural disturbance-based management objectives were formulated, providing guidelines on harvest agglomeration size and dispersion. Key words: temporal variability, boreal forest, fire regime, forest management, age distribution, fire size distribution, clearcut agglomeration size distribution


2009 ◽  
Vol 85 (6) ◽  
pp. 878-884 ◽  
Author(s):  
Lynn J Landriault ◽  
Brian J Naylor ◽  
Stephen C Mills ◽  
Dianna Lewis

Beavers (Castor canadensis) are widely considered a keystone species in boreal and northern temperate forest ecosystems and are seasonally dependent on intolerant hardwood tree species for food. We used existing data to investigate the effects of timber harvesting on the activity status of beaver lodges in central Ontario, Canada. Beaver lodges were initially visited from 1976 to 1979 and active lodges were revisited in 1994. We analyzed a sample of 100 lodges. Fifty had some timber harvesting within 400 m of the lodge, 41 of which had harvest within 100 m of the shoreline (subsequently referred to as shoreline harvest). We differentiated timber harvest by type (clearcut vs. partial cut), years since harvest, and location for each lodge. Clearcut timber harvesting appeared to have a positive effect on the occupancy of beaver lodges. Seventy-three percent of lodges adjacent to shoreline clearcut areas were active, whereas only 34% of lodges with no shoreline harvest were active. We developed logistic regression models to evaluate the relationship between presence of timber harvest and activity status based on harvest location, harvest type, years since harvest, and water feature (pond, stream, lake, or wetland). Using Akaike’s Information Criterion, our modeling suggested that the presence of a 21- to 35-year-old shoreline clearcut adjacent to a lodge, combined with the associated water feature type, was the best predictor of lodge activity. However, our dataset included only a small sample of lodges in this harvest category (n = 11). While these results are viewed as preliminary, they do suggest that further investigation into the effects of shoreline timber harvest and shoreline reserves on habitat suitability for beavers is warranted. Key words: beaver, beaver pond, boreal, clearcut, forestry, Great Lakes – St. Lawrence, natural disturbance, Ontario, partial harvest, riparian, shoreline


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