Paricá (Schizolobium amazonicum) and embaúba (Cecropia sp.) as new raw materials for particleboards
In this work two potential new species for forest plantation projects in Northern Brazil were evaluated for their suitability in particleboard production. The main evaluated parameters of the laboratory boards were pH value and buffer capacity of the particles, compaction ratio, thickness swelling, modulus of elasticity (MOE), modulus of rupture (MOR) and internal bond (IB). The results showed that both species are highly suitable for particleboard production as they presented low densities (400–430 kg/m³), light color, good compressibility and no apparent adverse reactions after UF-resination.
Enrichment planting in logging gaps with Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby: A financially profitable alternative for degraded tropical forests in the Amazon
Abstract Conservation of degraded forests is a challenging issue in the tropics, since the maintenance of environmental services and economic demands must be conciliated. Environmental services must be conserved while degraded tropical forests are demanded to be competitive against more financially profitable land uses as crop fields and pastures. The objective of this study was to evaluate productivity and financial profitability of enrichment planting in degraded forests. Seeds of Schizolobium parahyba var. amazonicum were planted in logging gaps of a 108-ha degraded forest in southeast Para (Brazil) in February 1995 (average = 91.7 seeds ha−1 and 15.3 seeds gap−1). After 13 years (2008), S. parahyba presented a volume increase of 3.1 m3 ha−1 yr−1 for individuals ⩾25 cm in DBH. More than 30% of the planted seeds were able to germinate, establish, and grow up to sizes ⩾25 cm in DBH. A cost-benefit analysis through Net Present Value (NPV) and a sensitivity analysis with different interest rates were performed to compare financial profitability of the treated and control area under roundwood and laminated plus sawnwood production. Enrichment planting using S. parahyba seeds presented higher NPVs in the treated than in control area for all simulations, except roundwood under interest rate of 9% per year.
Holocene climate change in the eastern Mediterranean region: a comparison of stable isotope and pollen data from Lake Gölhisar, southwest Turkey
Stable isotope and pollen data from Gölhisar Gölü, a small intramontane lake located in southwest Turkey, provide complementary records of Holocene climate change. Modern oxygen and hydrogen isotope water data are used as a means of comparing present‐day isotope composition of the lake water to the past oxygen isotope composition of the lake water as calculated from 18O/16O ratios in calcite precipitated in the summer months. Despite the lake system being chemically dilute, the modern isotope data clearly establish that the lake water is evaporated in relation to its spring input, suggesting that the palaeo data can be interpreted primarily in terms of changing precipitation/evaporation ratios. δ18O and δ13C values from authigenic calcite through the Holocene show predominantly negative values indicating climatic conditions wetter than today. Particularly notable are low (depleted) isotope values during the earliest Holocene (ca. 10 600–8800 cal. yr. BP), a period for which pollen data imply drier conditions than at present. This divergence between pollen‐inferred and stable isotope palaeoclimate data is found in other east Mediterranean lake sediment records, and suggests that vegetation may have taken several millennia to reach climatic equilibrium at the start of the Holocene. Isotopic fluctuations during the early‐to‐mid Holocene (8800–5100 cal. yr. BP) suggest oscillations between aridity and humidity. Higher δ18O and δ13C values for the second half of the Holocene indicate generally drier conditions than during the period before ca.5100 cal. yr BP although there is some evidence for increased humidity coinciding with pollen evidence for increasing human impact and intensification of agriculture, notably during the so‐called Beyşehir Occupation Phase (Classical and early Byzantine periods). The modern trend towards aridity started about 1300 yr ago. Copyright © 2006 John Wiley & Sons, Ltd.