B3 Improvement of forest management key strategies: a contribution to conservation and sustainable land use
PI(s) for this project:
Dr. Bernd Stimm
Prof. Dr. Reinhard Mosandl
Prof. Dr. Michael Weber
In spite of a variety of efforts, tropical forests are still threatened by exploitation and conversion to agricultural land-use. Besides legal protection, sustainable management concepts are essential for stable conservation of these ecosystems. This project aims at identifying and optimizing the potentials for forest management for three different ecosystems (Dry Forest, Tropical Mountain Rain Forest, Paramo) along a height- and climate gradient in Southern Ecuador. Therefore, multiple and locally differentiated aspects of forest management have to be considered: the direct provision of goods (timber and non-timber forest products) as well as ecosystem services (carbon sequestration, water regulation), which are of increasing importance; moreover, the effects of forest management on biodiversity and the impacts of climate change on resilience indicators and the potential distribution of selected species with high potential for sustainable management or conservation should be investigated. First of all, the most important forest structure types and possible improvements of management alternatives have to be identified at the three sites for the assessment of different management concepts. The alternatives will be tested on experimental field plots and consequently monitored for their impacts on the locally most important criteria of forest management. A sound decision support tool will be developed, taking into account uncertainties with regard to input parameters and the relevance of different criteria of forest management. Therefore, Multi Criteria Decision Analysis will be used to generate locally adapted management concepts for the different ecosystems. Those concepts should be able to consider the multiple functions of forest management and will represent the forestry component in sustainable land-use models. The comprehensive studies will be carried out in close cooperation with other scientific teams from Germany and Ecuador as well as local institutions of relevance for forest management. The direct involvement of Ecuadorian students and young academics and the integration of the investigations in educational concepts will contribute to capacity building and local efforts for the enhancement of environmental competencies. Moreover, the experimental field plots will serve in parts as demonstration objects for the implementation of sustainable forest management concepts.
In accordance with the different regional circumstances and purposes, suitable forest management concepts shall be developed based on strategies for optimized production, regulation of ecosystem services and resilience to global changes. Therefore, the guiding question is: ”How can strategies for the most important purposes on three selected ecosystems in Southern Ecuador be optimized and integrated in appropriate ecosystem management concepts?”
In the first step, the aim is to include the most relevant management strategies on selected sites: production, regulation of ecosystem services and robustness for global changes. The different criteria of these strategies have to be optimized in their respective performance, balanced for multi-objective forest management and integrated to land-use optimization on a landscape level (Fig. 1). The methodological framework for balancing the different criteria is given in multi criteria decision making (MCDM) techniques (Cohon 1978; Steuer 1986), which have been applied for a variety of forest management optimization problems (detailed explanations and comprehensive reviews on forestry related studies are given in Felbermeier & Mosandl 2003, Kangas & Kangas 2005, Diaz-Baltero & Romero 2008, Ananda & Herath 2009 or Felbermeier 2012) but only a low number of experiences in tropical forest management exist. Kuusipalo et al. (1997) for instance analysed strategies for sustained economic output from timber production with maintenance of environmental and sociocultural issues in Indonesian Borneo. Huth et al. (2004) have assessed logging scenarios for a tropical rain forest in Malaysia regarding to their yield, canopy opening and changes in species composition.
The hypothesis of the project is: “The optimization of the most relevant management activities improves the general outcome of resources and services without neglecting any of them.”
Fig. 1: Multi objective forest management regarding three kinds of objectives
Production of timber has been the most important task of forest management in the past century (FAO 2010). Even if the significance of other demands has increased, timber resources are still a crucial factor for the sustainable management on many forest sites.
Sustainable management of timber resources
The conversion of tropical mountain rain forest into pastoral lands is continuously going on due to the forests low contributions to current incomes of the land owners. Selective interventions are not executed in a sustainable manner but lead to ecological and economic degradation of the forests with conversion to pastoral land as a final consequence. Therefore, the production of timber resources has to be optimized in a sustainable framework. The effects of silvicultural interventions on the structure of the stands and their ability to provide the important environmental services have to be considered for the development of suitable management strategies. On the other hand, the pressure on the tropical mountain rain forest through demand for timber resources could be reduced by improved reforestation strategies for abandoned pastures.
NTFP tree species
The nutritional, social, economic, medicinal and traditional importance of some native NTFP tree species to rural communities in developing countries cannot be over-emphasized. These species provide food necessary for survival, provide rural employment, increase economic empowerment of the rural people and alleviate rural poverty. The current tree stocks of these species, which are largely in the wild, have been exploited for decades, thus leading to their over-exploitation with threat of extinction. For instance their fruit yield is decreasing because they are not managed, as a result of old age (senescence) and the fact that they have been harvested for decades. Consequently, the sustainability of these important native NTFP trees in providing their valued products is not guaranteed due to the low and decreasing yield on the one hand and the fact that they have not been domesticated on the other. There is therefore the need to urgently address this problem. Woody NTFP crops can be included in land-use concepts as a supplement or alternative for subsistence farmers and domestication appears to be a viable option with promising potentials.
This study is investigating the phenotypic variation of NTF products of dry forest tree species like Jatropha curcas, Bursera graveolens, Tabebuia chrysantha, Prosopis juliflora (some important NTFP species in the dry forest region of Laipuna, Ecuador; Sánchez et al. 2006a, Sánchez et al. 2006b).
Regulation of ecosystem services is, apart from production strategies, becoming more and more significant for sustainable forest management (FAO 2010):
Forests play a key role in climate change on a global scale as they can act as carbon sinks or sources, depending strongly on the relation of carbon accumulation and carbon loss through decomposition, respiration or harvesting (Houghton 1999, Nabuurs et al. 2008a, Klein et al. 2008). Due to these effects, forests and forest management are part of the Kyoto Protocol (Köhl et al. 2009). Beside the Kyoto Protocol, a so called “Voluntary Carbon Market” has been developed, where greenhouse gas (GHG) - emissions can be compensated, among other project types, via afforestation and reforestation. In order to fulfill the formal requirements for such ´emission tradings´, data bases on carbon stocks and sequestration rates are needed for different forest types, site qualities, and management regimes. Since the function of forests as carbon sinks and sources is commonly accepted, there are many studies about forests and their role in the global carbon cycle worldwide (e.g. Pan et al. 2011, Wirth & Lichtstein 2009). However, there is still a lack of information in many regions and forest types regarding C-dynamics in the different forest ecosystem compartments, especially in tropical zones (De Fries et al. 2010) and the interaction with other management aims (e.g. deKoning 2005, Olschewski & Benitez 2005, Knoke & Weber 2006, Wunder 2008). Nevertheless, several studies have indicated the potential of plantations or secondary forests in Ecuador for carbon sequestration (e.g. Fehse et al. 2002, Olschewski & Benitez 2005, Wunder 2008).
Mountains contribute at least half of the global freshwater resources (Celleri et al. 2007). The water resource represents an economic and ecological potential in the tropical Andes, for instance, for domestic and industrial uses, irrigates agricultural lands and generates hydropower electricity (Celleri & Feyen 2009). In case of the Cajas National Park and its surrounding the area is mainly dominated by páramo, a type of open grassland vegetation consisting of large tussock grass, low shrubs, and herbs (Hofstede et al. 2002). However, there are patches of natural forest with Polylepis spp. (tree of quinua) as the most representative. Furthermore, it is possible to find relicts of Cloudy forests located between Llaiucu and Taitachugo lakes and the Forest of Mazan, the latter located on the border out of the National Park. Apparently, there is a relationship between water cycle and vegetation along with soils physical properties and climate (Celleri & Feyen 2009, Crespo et al. 2011). As typical in other natural ecosystems of Ecuador, there is a strong land transformation conducted by landowners out of the limits of the national park, forming a new landscape composed by pine plantations, agriculture lands, crops and pastures.
Andean ecosystems are very fragile to land use change, resulting in negative effects on the water cycle due to soil compaction and erosion causing a decrease in water yield and loss of catchment regulation (Bruijnzeel 2004). Exotic tree plantations such as Pinus radiata and Pinus patula have been used in Paramo as an effective way to expand the economic viability despite the low growth rate at that high elevation (Buytaert et al. 2007). However, these plantations also have negative impacts on water balance because they absorb high amounts of water and consequently effect lower soil water content (Hofstede et al. 2002), but little is known yet about these facts on the Paramo ecosystem.
Global changes, mainly driven through climate change as well as growing populations and living standards, are affecting the ecosystems around the world. We want to address two major issues, biodiversity conservation (Secretariat of the Convention on Biological Diversity 2010) and climate change (Stern 2006):
The ecosystems of the tropical mountain rain forest as well as the Tumbesian dry forest are considered to be one of the most biodiverse ecosystems in the world. For this reason, forest management has to take into account the effects of silvicultural interventions on species diversity or contain biodiversity forcing measures. The impact of removing competitors of commercially valuable trees on biodiversity indicators, like alpha-diversity of epiphytes and moths, has been evaluated in the framework of FOR 412/816 at the Tropical mountain rain forest site (Günter et al. 2008). However, the regeneration of tree species needs to be analyzed in the long run, leading to future composition and structure of the affected stands. Moreover, genetic diversity is fundamental for the resilience of populations against overexploitation, fragmentation and adaptation to climate change.
The region of Loja represents a broad range of different ecological conditions, from tropical dry forests over tropical humid forest to the Paramo regions. Günter et al. (2003) estimated about 134 potential gene-ecological zones in the region indicating an extraordinary high potential of gene-ecological diversity of key species for sustainable management and conservation. The conservation of this gene pool is of high priority for restoration purposes, especially regarding the high pressure from deforestation, degradation and climate change. For adaptation to climate change and for the selection of appropriate plant material it is important to identify different provenances and test their reaction under different ecological conditions and climate change scenarios. This information will strongly contribute to recent efforts of the Ecuadorian government in the establishment of a network of biological corridors enhancing landscape connectivity, adaptation to climate change and the development of climate-smart management concepts.
The studies will be carried out on three different sites:
i) Tropical mountain rain forest (Estación Cientifica San Francisco, ECSF)
ii) Dry Tumbesian forest (Laipuna reserve)
iii) Paramo (Cajas National Park)
The work programme is separated in the following three parts (Fig. 1):
A) Optimization of relevant forest management alternatives: Identification and evaluation of relevant management alternatives and objectives as well as experiments and tests concerning effects of alternative strategies on production and regulation of ecosystem services.
B) Accounting for global changes: Modeling of impact of climate scenarios on spatial distribution of key species for conservation and sustainable management on a regional level. Identification of potential provenances of both, species for conservation and with high potential for use of timber and NWFPs and testing of resilience indicators to climate change. Conclusions about sustainable management perspectives under climate change scenarios.
C) Balancing of alternative strategies for multi objective forest management: Possible forest management alternatives are evaluated in accordance with different decision criteria in order of identifying the management consequences on a stand level.