Forest dynamics

Geonoma orbignyana is a common understory palm, whose leaves are used as foliage in Colombia. This palm has been used for more than 30 years; but there is no information about its life history or conservation status. Our objective was to characterize the life history of this palm and population dynamics of a natural population as a first step to assess the effect of leaf harvesting. More than 1600 palms were monitored from June 1999 to March 2000; we measured growth, mortality, and reproductive success. Population dynamics were evaluated using a Lefkovitch matrix model, and elasticity analysis. Results indicate that G. orbignyana grows at a rate of 1.98 ± 0.047 leaves/year, the palm has a long lifespan, and growth and reproduction are related to light conditions in the forest. The density of this palm is high (108–311 palms/100 m2), which is explained in part by its capacity to continue growing after damage, and to respond to the frequent gap formation in the forest. The population is growing (λ = 1.074, CI = [1.046–1.099]). Survival transitions account for 77% of population growth, a value that is higher compared to other understory plants. Because of the high density, the recovery capacity of these palms, and the correlations found between individual and population performances with forest dynamics, we hypothesize that G. orbignyana behaves as an opportunistic species taking advantage of forest gaps. This palm is a promising non-timber forest product (NTFP) with a high profile for further exploitation, although we recommend that harvesting regimens should consider time of recovery and forest dynamics. Without these considerations mortality could increase in all classes, which will compromise population persistence. Further studies should accurately estimate the recovery time after defoliation as well as to characterize forest dynamics identifying its most important features for population growth.

The regeneration of forest resources is one of the main objectives of modern forest management. The present book is based on my personal PhD thesis and aims to identify detailed features of the regeneration process and the characteristics of sapling interaction. The research involved evaluation of regeneration structure, dimensional differentiation of saplings, spatial pattern analysis - sapling aggregation and species association,  and sapling competition using distance-dependent methods. A new distance-dependent dimensional differentiation index (IDIV) and a new geometrical criterion for selecting neighbouring competitor saplings were created and applied. Appropriate methods and techniques were identified for investigating regeneration and computer technology was used intensively. Nine stand-alone software programs were produced in order to achieve the objectives of the thesis.

Natural disturbances play a key role in ecosystem dynamics and are important factors for sustainable forest ecosystem management. Quantitative models are frequently employed to tackle the complexities associated with disturbance processes. Here we review the wide variety of approaches to modelling natural disturbances in forest ecosystems, addressing the full spectrum of disturbance modelling from single events to integrated disturbance regimes. We applied a general, process-based framework founded in disturbance ecology to analyze modelling approaches for drought, wind, forest fires, insect pests and ungulate browsing. Modelling approaches were reviewed by disturbance agent and mechanism, and a set of general disturbance modelling concepts was deduced. We found that although the number of disturbance modelling approaches emerging over the last 15 years has increased strongly, statistical concepts for descriptive modelling are still largely prevalent over mechanistic concepts for ex...

In literature on Natural Resource Management related policies in Africa and Cameroon in particular, Colonial heritage was defined and identified. The question of this paper is whether "community forestry" which promotes giving back the forest to people breaks with this tradition. The key elements of Colonial heritage in resource management were deduced from literature. Based on these benchmarks the program and practice of community forestry in Cameroon were evaluated. Data about community forestry in Cameroon was collected in 10 selected communities in 2009/10. Today in practice community forestry favors techno-scientific knowledge about the forest, separate nature from human life, is a bureaucratic controlled engagement with nature and is aimed to make nature and people productive. The benchmark identifies a strong Colonial heritage within community forestry in Cameroon and questions whether the aim of including the local people in forest management, correcting their previous exclusion by the Colonial policy in the management of their forest resources, thus, the self determined life of people within the forest can be reached.

The primary deciduous forests in the Eastern Ghats (EG) of Tamil Nadu (TN) India have undergone many changes owing to various need-based forest managements, such as timber extraction for industry, railway sleepers, charcoal, and forest clearance for hydroelectric projects and agriculture, during preindependence and postindependence periods (i.e., from 1800 to 1980). The enactment of a forest conservation act during the 1980s changed the perception of forest managers from utilization to conservation. This study was taken up to assess the forests dynamics in the EG of TN spatially between 1990 and 2003 and nonspatially between 1900 and the 1980s. Landsat Thematic Mapper (TM) and Indian Remote Sensing satellite (IRS) 1D Linear Imaging and Self Scanning (LISS III) data were used to assess forests during 1990 and 2003, respectively. Field floristic survey and secondary data (such as published literature, floras, books, and forest working plans) were used to assess the forest dynamics in terms of forest type and species composition among the preindependence period, the postindependence period, and the present (i.e., before and after 1980). The satellite data analysis revealed a considerable amount of changes in all forest types during the 13 years. The comparison of species composition and forest types between the past and present revealed that need-based forest management along with anthropogenic activity have altered the primary deciduous forest in to secondary and postextraction secondary forests such as southern thorn and southern thorn scrub forests in the middle [400–900 m above mean sea level (MSL)] and lower slopes (<400 m MSL). However, the evergreen forests present at the upper slope (>900 m MSL) and plateau seemed not to be much affected by the forest management. The changes estimated by the satellite data processing in the major forest types such as evergreen, deciduous, southern thorn, and southern thorn scrub are really alarming because these changes have occurred after the implementation of a forest conservation act. The dependence of local people on forests for various purposes in this region is also considerably high, which might be a key factor for the changes in the forests. The results of this study not only provide an outlook on the present status of the forests and the change trends but also provide the basis for further studies on forests in the EG of TN.