How persistent are the impacts of logging roads on Central African forest vegetation?

Logging roads can trigger tropical forest degradation by reducing the integrity of the ecosystem and providing access for encroachment. Therefore, road management is crucial in reconciling selective logging and biodiversity conservation. Most logging roads are abandoned after timber harvesting; however, little is known about their long-term impacts on forest vegetation and accessibility, especially in Central Africa. In 11 logging concessions in the Congo Basin, we field-sampled a chronosequence of roads that, judging from satellite images, had been abandoned between 1985 and 2015. We assessed recovery of timber resources, tree diversity and above-ground biomass in three zones: the road track, the road edge (where forest had been cleared during road construction) and the adjacent logged forest. The density of commercial timber species <15 cm d.b.h. was almost three times higher in the road track (321 individuals ha−1) and edge (267) than in the logged adjacent forest (97). Over time, tree species diversity converged to a comparable level between roads and adjacent forests, along with an increase in canopy closure. The average width of forest clearing for road construction was 20 m, covering a total 0·76% of the forest area inside concessions. After 15 years following abandonment, road tracks had recovered 24 Mg ha−1 of above-ground woody biomass, which was 6% of that in the adjacent forest, while road edges had accumulated 167 Mg ha−1 (42%). Ten years after abandonment, roads were no longer penetrable by poachers on motorcycles. An exotic herb species was fully replaced by dominant Marantaceae that have even higher abundance in the adjacent forest. • Synthesis and applications. Our evidence of vegetation recovery suggests that logging roads are mostly transient elements in the forest landscapes. However, given the slow recovery of biomass on abandoned road tracks, we advocate both reducing the width of forest clearing for road construction and reopening old logging roads for future harvests, rather than building new roads in intact forests. Road edges seem suitable for post-logging silviculture which needs to be assisted by removing dominant herbs during the early years after abandonment while the road track is still accessible. (Résumé d'auteur

Well-being, work comfort and food security are better than maximizing production in the Amazon.

In the Amazon, slash and burn is the most common technique used by American-Indians, small farmers and even big ranches to transform forests into rural landscapes. The basis of food subsistence for diverse populations (rice, corn and bean), slash and burn is also a must for the plantation of cocoa, coffee, palms and pastures. The Amazonian rural landscape is currently dominated by pastures, occupying around 80 % of the deforested surface. Even if the nature of the plantation varies according to location, height, soil type and local traditions, slash and burn remains relatively the same in all regions. Agro-ecological intensification and the integration of livestock and agriculture is 2-3 decades old. Different alternatives have been tested, particularly the introduction of leguminous (covering the land or forming trees) to improve the soil and to build a bank of proteins for cattle. New techniques for the recuperation of pasture lands have become widely popular among ranches. The introduction of one or two annual plantations between two pasture areas allows reestablishing fertility through the injection of nitrates and, as a result, increases the pasture?s productivity. However, being relatively high-cost because of its demand in terms of mechanization and inputs, this technique is almost unaffordable for small Amazonian farmers..

Trade-Offs Between Carbon Stocks and Timber Recovery in Tropical Forests are Mediated by Logging Intensity

Forest degradation accounts for ~70% of total carbon losses from tropical forests. Substantial emissions are from selective logging, a land-use activity that decreases forest carbon density. To maintain carbon values in selectively logged forests, climate change mitigation policies and government agencies promote the adoption of reduced-impact logging (RIL) practices. However, whether RIL will maintain both carbon and timber values in managed tropical forests over time remains uncertain. In this study, we quantify the recovery of timber stocks and aboveground carbon at an experimental site where forests were subjected to different intensities of RIL (4, 8, and 16 trees/ha). Our census data span 20 years postlogging and 17 years after the liberation of future crop trees from competition in a tropical forest on the Guiana Shield, a globally important forest carbon reservoir. We model recovery of timber and carbon with a breakpoint regression that allowed us to capture elevated tree mortality immediately after logging. Recovery rates of timber and carbon were governed by the presence of residual trees (i.e., trees that persisted through the first harvest). The liberation treatment stimulated faster recovery of timber albeit at a carbon cost. Model results suggest a threshold logging intensity beyond which forests managed for timber and carbon derive few benefits from RIL, with recruitment and residual growth not sufficient to offset losses. Inclusion of the breakpoint at which carbon and timber gains outpaced postlogging mortality led to high predictive accuracy, including out-of-sample R2 values \u3e90%, and enabled inference on demographic changes postlogging. Our modeling framework is broadly applicable to studies that aim to quantify impacts of logging on forest recovery. Overall, we demonstrate that initial mortality drives variation in recovery rates, that the second harvest depends on old growth wood, and that timber intensification lowers carbon stocks

Effect of logging wounds on diameter growth of beech (Fagus orientalis Lipsky) trees following selection cutting in Caspian forests of Iran

Background Logging damage to residual trees during selection cutting may lead to serious economic losses in terms of both timber quality and diameter growth reduction. In this study, we investigated the effect of logging operations on residual tree damage and the consequence of injuries on diameter growth in an uneven-aged mixed forest dominated by beech (Fagus orientalis Lipsky)

Plantio direto em áreas alteradas na agricultura familiar.

bitstream/item/38628/1/Plantio-Direto.pdfCartilha

Rapid tree carbon stock recovery in managed Amazonian forests.

While around 20% of the Amazonian forest has been cleared for pastures and agriculture, one fourth of the remaining forest is dedicated to wood production [1] . Most of these production forests have been or will be selectively harvested for commercial timber, but recent studies show that even soon after logging, harvested stands retain much of their tree-biomass carbon and biodiversity [2,3] . Comparing species richness of various animal taxa among logged and unlogged forests across the tropics, Burivalova et al.[4] found that despite some variability among taxa, biodiversity loss was generally explained by logging intensity (the number of trees extracted). Here, we use a network of 79 permanent sample plots (376 ha total) located at 10 sites across the Amazon Basin [5] to assess the main drivers of time-to-recovery of post-logging tree carbon ( Table S1 ). Recovery time is of direct relevance to policies governing management practices (i.e., allowable volumes cut and cutting cycle lengths), and indirectly to forest-based climate change mitigation interventions

The tropical managed forests observatory: a research network addressing the future of tropical logged forests.

While attention on logging in the tropics has been increasing, studies on the long-term effects of silviculture on forest dynamics and ecology remain scare and spatially limited. Indeed, most of our knowledge on tropical forests arises from studies carried out in undisturbed tropical forests. This biasis problematic given that logged and disturbed tropical forests are now covering a larger area thantheso-alled primary forests. A new network of permanent sample plots in logged forests, the Tropical managed Forests Observatory (TmFO), aims to ?ll this gap by providing unprecedented opportunities to examine long-term data on the resilience of logged tropical forests at regional and global scales. TmFO currently includes 24 experimental sites distributed across three tropical regions, with a total of 490 permanent plots and 921 ha of forest inventories

Postherpetic Neuralgia: Role of Gabapentin and Other Treatment Modalities

Postherpetic neuralgia (PHN) is a chronic and painful condition that may occur after a herpes zoster infection. The frequency of PHN after untreated zoster varies widely. Age is the most important risk factor for development of PHN. The condition occurs in an estimated 50% of patients older than 50 years. The pain of PHN can be severe and debilitating and is frequently associated with allodynia. Although in most patients pain remits within the first year, it may persist for a lifetime. Tricyclic antidepressants (TCAs), topical agents, opioids, and gabapentin, a structural Γ-amino butyric acid (GABA) analogue, are the only agents that have demonstrated efficacy in randomized clinical trials for treatment of both the shooting and the burning form of pain associated with PHN. TCAs are among the most commonly used classes of agents for treating PHN and are effective in a significant proportion of patients. However, various adverse events can limit treatment. These side effects tend to be more acute in the elderly, the population most likely to suffer from PHN. Topical agents have led to mild to moderate improvement in patients with PHN but are usually ineffective as monotherapy for this condition. Until recently, carbamazepine was the only antiepileptic drug evaluated for the treatment of PHN. Over the past few years, however, gabapentin has received increasing attention as a useful treatment for neuropathic pain. Gabapentin lacks significant drug-drug interactions and has a favorable safety profile, which makes it particularly useful for treatment of PHN.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65597/1/j.1528-1157.1999.tb00933.x.pd

Chapter 29: Restoration Priorities and Benefits within Landscapes and Catchments and Across the Amazon Basin

Restoration can be applied in many different Amazonian contexts but will be most effective at leveraging environmental and social benefits when it is prioritized across the Amazon Basin and within landscapes and catchments. Here we outline the considerations that are most relevant for planning and scaling restoration