Old-growth forests: Data gaps and challenges

2003 ◽  
Vol 79 (3) ◽  
pp. 645-651 ◽  
Author(s):  
Ole Hendrickson

How much old growth is there? How much was there? Is remaining old growth disappearing? If so, how fast and why? Is any more old growth being created? How fragmented are old-growth forests? What other forest types and land uses surround them? Scientists see these as challenging questions, never to be fully resolved. Policy makers see information gaps and want answers. They assume that because the public values old-growth forests, their continuing availability must be assured. Forest managers need to be convinced that old-growth forests provide unique values before taking costly measures to conserve them. The relative stability of old-growth forests is interesting from a management perspective. Are old-growth forests more resistant to high-intensity disturbances, such as crown fires and violent storms? Do they resist insect outbreaks? A related issue is the quality of ecosystem services provided by old-growth forests. Do they have an exceptional ability to provide clean water, to stabilize hydrologic regimes, and to moderate local climates? Can they be used to test hypotheses about complexity, stability, resilience, and ecosystem change? These questions provide a strong rationale for developing working definitions of old-growth forests, for retaining areas of old-growth forest, and for replicating old-growth features in landscapes managed for timber production. Old-growth forests are desirable sites for monitoring, serving as benchmarks for adaptive management. Knowledge about old-growth forests has already had a considerable impact on policy and management, particularly in coastal regions. Current research and monitoring systems may not be adequate for the task of identifying and describing the biological complexity and diversity inherent in old-growth forests. New investments in collecting and managing data from old-growth (and secondary) forests are needed, and will pay manifold dividends to future generations of Canadians. This paper suggests that the central role of old-growth forests in developing sustainable forest management should create an incentive for the forest science, policy, and management communities to unite in support of their conservation. Key words: biodiversity, gene conservation, resilience, ecosystem approach, information management, ecosystem services

2020 ◽  
Vol 50 (2) ◽  
pp. 155-169 ◽  
Author(s):  
Maxence Martin ◽  
Nicole J. Fenton ◽  
Hubert Morin

The erosion of old-growth forests in boreal managed landscapes is a major issue currently faced by forest managers; however, resolving this problem requires accurate surveys. The intention of our study was to determine if historic operational aerial forest surveys accurately identified boreal old-growth forests in Quebec, Canada. We first compared stand successional stages (even-aged vs. old-growth) in two aerial surveys performed in 1968 (preindustrial aerial survey) and 2007 (modern aerial survey) on the same 2200 km2 territory. Second, we evaluated the accuracy of the modern aerial survey by comparing its results with those of 74 field plots sampled in the study territory between 2014 and 2016. The two aerial surveys differed significantly; 80.8% of the undisturbed stands that were identified as “old-growth” in the preindustrial survey were classified as “even-aged” in the modern survey, and 60% of the stands identified as “old-growth” by field sampling were also erroneously identified as “even-aged” by the modern aerial survey. The scarcity of obvious old-growth attributes in boreal old-growth forests, as well as poorly adapted modern aerial survey criteria (i.e., criteria requiring high vertical stratification and significant changes in tree species composition along forest succession), were the main factors explaining these errors. It is therefore likely that most of Quebec’s boreal old-growth forests are currently not recognized as such in forest inventories, challenging the efficacy of sustainable forest management policies.


2009 ◽  
Vol 85 (5) ◽  
pp. 762-771 ◽  
Author(s):  
Gordon M Hickey

The debate surrounding Tasmania’s old-growth forests in 2004 represents a good example of a situation where, despite both sides of a highly polarized policy field drawing on science to support their world view (to varying degrees), little common ground was found to enable robust and shared discussions that were required to resolve the conflict and collectively define a sustainable future for Tasmania’s old-growth forests. This paper reviews the scientific and policy-related literature on old-growth eucalypt forests and outlines recent developments in old-growth forest policy in Tasmania. It describes the highly polarized public policy debate surrounding Tasmania’s old-growth forests in the lead up to the 2004 Federal election, and considers the challenges posed by polarized democratic debate when developing public policy. It then considers the different dimensions of forest-related scientific knowledge and discusses the role of science in informing and resolving the polarized old growth debate in Tasmania. Key words: Sustainable forest management, strategy, politics, research, government, Australia


2011 ◽  
Vol 27 (03) ◽  
pp. 323-326 ◽  
Author(s):  
Gregory R. Goldsmith ◽  
Liza S. Comita ◽  
Siew Chin Chua

Secondary forests occupy a growing portion of the tropical landscape mosaic due to regeneration on abandoned pastures and other disturbed sites (Asneret al. 2009). Tropical secondary forests and degraded old-growth forests now account for more than half of the world's tropical forests (Chazdon 2003), and provide critical ecosystem services (Brown & Lugo 1990, Guariguata & Ostertag 2001).


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Martina Alrutz ◽  
Jorge Antonio Gómez Díaz ◽  
Ulf Schneidewind ◽  
Thorsten Krömer ◽  
Holger Kreft

Background: Tropical montane forests are important reservoirs of carbon and biodiversity but are threatened by deforestation and climate change. It is important to understand how forest structure and aboveground biomass change along gradients of elevation and succession. Questions: What are the interactive effect of elevation and two stages of succession on forest structure parameters? Studied species: Tree communities. Study site and dates: Cofre de Perote, Veracruz, Mexico. August to December 2015. Methods: We studied four sites along an elevational gradient (500, 1,500, 2,500, and 3,500 m). At each elevation and each forest type, we established five 20 × 20 m plots (n = 40 plots). Within each plot, we measured stem density, mean diameter at breast height (dbh), and tree height and derived basal area and aboveground biomass (AGB). Results: AGB peaked at 2,500 m and was significantly related to elevation and succession, with higher values in old-growth forests than in secondary forests at higher altitudes. Lower values of mean dbh and basal area were found at higher elevations. At the lowest elevation, both successional stages had the same values of stem density and AGB. At both lower elevations, secondary forests had higher values of dbh and basal area. There were high biomass stocks in the old-growth forest at 2,500 and 3,500 m. Conclusions: Old-growth forests at higher elevations are threatened by deforestation, consequently these remaining fragments must be preserved because of their storage capacity for biomass and their ability to mitigate climate change.


2021 ◽  
Vol 4 ◽  
Author(s):  
Maxence Martin ◽  
Pierre Grondin ◽  
Marie-Claude Lambert ◽  
Yves Bergeron ◽  
Hubert Morin

Large primary forest residuals can still be found in boreal landscapes. Their areas are however shrinking rapidly due to anthropogenic activities, in particular industrial-scale forestry. The impacts of logging activities on primary boreal forests may also strongly differ from those of wildfires, the dominant stand-replacing natural disturbance in these forests. Since industrial-scale forestry is driven by economic motives, there is a risk that stands of higher economic value will be primarily harvested, thus threatening habitats, and functions related to these forests. Hence, the objective of this study was to identify the main attributes differentiating burned and logged stands prior to disturbance in boreal forests. The study territory lies in the coniferous and closed-canopy boreal forest in Québec, Canada, where industrial-scale logging and wildfire are the two main stand-replacing disturbances. Based on Québec government inventories of primary forests, we identified 427 transects containing about 5.5 circular field plots/transect that were burned or logged shortly after being surveyed, between 1985 and 2016. Comparative analysis of the main structural and environmental attributes of these transects highlighted the strong divergence in the impact of fire and harvesting on primary boreal forests. Overall, logging activities mainly harvested forests with the highest economic value, while most burned stands were low to moderately productive or recently disturbed. These results raise concerns about the resistance and resilience of remnant primary forests within managed areas, particularly in a context of disturbance amplification due to climate change. Moreover, the majority of the stands studied were old-growth forests, characterized by a high ecological value but also highly threatened by anthropogenic disturbances. A loss in the diversity and functionality of primary forests, and particularly the old-growth forests, therefore adds to the current issues related to these ecosystems. Since 2013, the study area is under ecosystem-based management, which implies that there have been marked changes in forestry practices. Complementary research will be necessary to assess the capacity of ecosystem-based management to address the challenges identified in our study.


2013 ◽  
Vol 29 (4) ◽  
pp. 301-311 ◽  
Author(s):  
Julieta Benítez-Malvido ◽  
Miguel Martínez-Ramos

Abstract:Plant survival and growth in tropical rain forest are affected by different biotic and abiotic forces. As time elapses and plants grow the relative importance of such forces as regeneration inhibitors and/or facilitators may change according to habitat and species. To detect within- and among-species divergences in performance over time in different habitats we followed, for nearly a decade, the survival, growth and herbivory of seedlings of the native tree species: Chrysophyllum pomiferum, Micropholis venulosa and Pouteria caimito. In Central Amazonia, young seedlings were planted into old-growth and secondary forests dominated by Vismia spp. One year after planting, C. pomiferum ranked first (i.e. fast growth, fewer dead and less herbivory) for both habitats, followed by M. venulosa and P. caimito. Initial trends changed over time. In the long term, M. venulosa ranked first for both habitats, followed by C. pomiferum and P. caimito ranked consistently lowest. Within-species divergences in growth and herbivory were greater in secondary forest. Initial seedling responses cannot always be used to predict species persistence in the long term. Contrary to previous estimations, old-growth-forest species can persist under Vismia spp. stands, at least when planted.


1985 ◽  
Vol 61 (2) ◽  
pp. 180-184 ◽  
Author(s):  
F. W. Bunnell

Prior to 1970, research on the relationships between black-tailed deer and forestry practices was largely restricted to areas of low snowfall. Findings suggested that deer populations responded positively to the increased forage generated by timber harvesting practices, and forestry was assumed to be beneficial to black-tailed deer. The first research in areas of high snowfall obtained contrary results; in fact, old-growth forests were found to be valuable habitats for deer. Subsequent research documented that there were four major reasons why old-growth forests provided ideal winter habitat: reduced costs of locomotion in snow, lower rates of food burial, provision of arboreal lichen, and a more heterogeneous, fine-grained environment. Initial research findings encouraged harvesting guidelines that temporarily reserved tracts of old growth as winter ranges. The guidelines were enacted while research, would eventually suggest alternative approaches, continued to examine functional relationships. Current solutions to the conflict include intensive, specific silvicultural practices to mimic old-growth features in managed stands. Review of the conflict provides several lessons of broader applicability.


2021 ◽  
Vol 4 ◽  
Author(s):  
Jeffrey Opoku-Nyame ◽  
Alain Leduc ◽  
Nicole J. Fenton

Clear cut harvest simplifies and eliminates old growth forest structure, negatively impacting biodiversity. Partial cut harvest has been hypothesized (1) to have less impact on biodiversity than clear cut harvest, and (2) to encourage old growth forest structures. Long-term studies are required to test this hypothesis as most studies are conducted soon after harvest. Using epixylic bryophytes as indicators, this study addresses this knowledge gap. Fourteen years after harvest, we examined changes in epixylic bryophyte community composition richness and traits, and their microhabitats (coarse woody debris characteristics and microclimate) along an unharvested, partial cuts and clear cuts harvest treatment in 30 permanent plots established in the boreal black spruce (Picea mariana) forests of northwestern Quebec, Canada. Our results were compared to those of an initial post-harvest study (year 5) and to a chronosequence of old growth forests to examine species changes over time and the similarity of bryophyte communities in partial cut and old growth forests. Coarse woody debris (CWD) volume by decay class varied among harvest treatments with partial cuts and clear cuts recording lower volumes of early decay CWD. The epixylic community was richer in partial cuts than in mature unharvested forests and clear cuts. In addition, species richness and overall abundance doubled in partial and clear cuts between years 5 and 14. Species composition also differed among treatments between years 5 and 14. Furthermore, conditions in partial cut stands supported small, drought sensitive, and old growth confined species that are threatened by conditions in clear cut stands. Lastly, over time, species composition in partial cuts became more similar to old growth forests. Partial cuts reduced harvest impacts by continuing to provide favorable microhabitat conditions that support epixylic bryophytes. Also, partial cut harvest has the potential to encourage old growth species assemblages, which has been a major concern for biodiversity conservation in managed forest landscapes. Our findings support the promotion of partial cut harvest as an effective strategy to achieve species and habitat conservation goals.


Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 442 ◽  
Author(s):  
Paúl Eguiguren ◽  
Richard Fischer ◽  
Sven Günter

Anthropogenic activities such as logging or forest conversion into agricultural lands are affecting Ecuadorian Amazon forests. To foster private and communal conservation activities an economic incentive-based conservation program (IFC) called Socio Bosque was established. Existing analyses related to conservation strategies are mainly focused on deforestation; while degradation and the role of IFC to safeguard ecosystem services are still scarce. Further on, there is a lack of landscape-level studies taking into account potential side effects of IFC on different forest types. Therefore we assessed ecosystem services (carbon stocks, timber volume) and species richness in landscapes with and without IFC. Additionally, we evaluated potential side-effects of IFC in adjacent forest types; hypothesizing potential leakage effects of IFC. Finally, we tested if deforestation rates decreased after IFC implementation. Forest inventories were conducted in 72 plots across eight landscapes in the Ecuadorian Central Amazon with and without IFC. Plots were randomly selected within three forest types (old-growth, logged and successional forests). In each plot all individuals with a diameter at breast height greater than 10 cm were measured. Old-growth forests in general showed higher carbon stocks, timber volume and species richness, and no significant differences between old-growth forests in IFC and non-IFC landscapes were found. Logged forests had 32% less above-ground carbon (AGC) and timber volume in comparison to old-growth forests. Surprisingly, logged forests near IFC presented higher AGC stocks than logged forests in non-IFC landscapes, indicating positive side-effects of IFC. Successional forests contain 56% to 64% of AGC, total carbon and timber volume, in comparison to old-growth forests, and 82% to 87% in comparison to logged forests. Therefore, successional forests could play an important role for restoration and should receive more attention in national climate change policies. Finally, after IFC implementation deforestation rate decreased on parish level. Our study presents scientific evidence of IFC contribution to conserving ecosystem services and species richness. In addition IFC could help indirectly to reduce degradation effects attributed to logging, indicating potential compatibility of conservation aims with forest activities at a landscape level.


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