Fire protection of a laminated veneer lumber joint by wood carbon phenolic spheres sheeting

Laminated veneer lumber joints made with metal plate connectors were protected with wood carbon phenolic spheres (CPS) sheeting and tested for creep under fire. The effects of the carbonizing temperature of charcoal, used as raw material for the CPS sheets, the thickness, and the location of the sheet on the joint regarding the fire-resistance performance of the joint were studied. The time to rupture of the joints covered with CPS sheets made from charcoal carbonized at 800°C (CPS800) was slightly prolonged compared with that of uncovered joints. On the other hand, the time to rupture of CPS sheets made from charcoal carbonized at 1600°C (CPS1600) was markedly extended. The changes in the charcoal properties due to increasing the carbonizing temperature might be the main reason the CPS1600 sheets had higher fire-resistance performance. The thickness and location of CPS1600 sheets have significant effects on the fire resistance of the joint. A highly fire-resistant laminated veneer lumber joint was obtained using a CPS1600 sheet. The CPS1600 sheet with a thickness of 3mm covering three sides of the joint prolonged the time to rupture 16-fold compared with that of unprotected joints.Part of this paper was presented at the 4th International Wood Science Symposium, Serpong, Indonesia, September 2002     

Harnessing forest ecological sciences in the service of stewardship and sustainability: A perspective from ‘down-under’

Australia's native forests are predominantly Crown land, managed by the States. Regional Forest Agreements between four of the States and the Federal Government (1997–2001) resulted in a 36% increase in the area of conservation reserves and a 15% decrease in area of multiple-use (including timber harvesting) forests. The limited acceptance of timber harvesting in native forests, together with the rapid expansion of hardwood plantations, has diverted research focus away from native forests. Recent events including a prolonged drought and two forest fires totaling more than 3 million ha should have stimulated research in native forests on the effects of fire on ecosystem processes, on the management of fire and on management of water catchments; fires, far more than logging, are shaping our native forests in recent times. In particular, the use of prescribed fire to reduce fuels has decreased. We argue that Australian research effort in native eucalypt forests is lacking in two key areas – the effects of fire on carbon storage in forests and soils, and on the management of water yield from forested catchments. The results of forest research are variously published in the scientific journals, and increasingly in consultancy reports to governments or a to a range of organizations and industries. The question of who does the harnessing of knowledge coming from the science of forest ecology is compounded by constant changes in both political and management arrangements. If forest science is to assume a greater role in politics and forest management in Australia, scientists must enter the foray, using the fighting words of politics rather than maintaining the protective mantle of neutrality. With research in native forests being continually downgraded at both State and Federal levels, we take a somewhat less than optimistic view about how well ecological sciences will be harnessed in the service of forest stewardship and sustainability in Australia.     

Management effects on carbon stocks and fluxes across the Orinoco savannas

Across the physiognomic types of the Orinoco llanos, periodic inventories and changes in land-use between 1982–1992 are estimated. Results indicate that the area under pastures and forest plantations is increased by 0.005337×10⁶ km², whilts reducing the area of croplands by 0.000119×10⁶ km². This is a net increase of 0.005218×10⁶ km². The gross carbon release is 174.66 Tg C per year to the atmosphere and transferring from cultivated and native vegetation to wood products (1.62 Tg C per year) and slash (1.18 Tg C per year). The processes of land preparation contribute 1.40 Tg C per year to the atmosphere. From the tree savannas, woodlands and forests 0.73 Tg C per year are estimated to have been transferred to the soil following clearance and burning over this period, and 1.05 Tg C per year from herbaceous savannas when were buried and decomposed at 0.84 Tg C per year. The estimate of carbon balance here by inventories and changes in land-use approach indicates that the Orinoco llanos is a sink of −17.53 Tg C per year. The carbon turnover time in the Orinoco system is 68 years, which provides a limited route for carbon sequestration. The calculated potential of the Orinoco llanos for storing carbon is 8300 Tg C. Ecological options to achieve this potential value are addressed. However, nutrient deficiency and seasonal water supply are serious drawbacks to take into account for increasing carbon accretion. These results are particular for the Orinoco llanos, even though described processes could be similar to world-wide savannas, where a gradient of carbon heterogeneity exists.     

Rapid production of high-strength cement-bonded particleboard using gaseous or supercritical carbon dioxide

This study deals with the effects of curing treatment with gaseous and supercritical carbon dioxide on the properties of cement-bonded particleboard (CBP) manufactured by the conventional cold-pressing method. The hydration of cement and the mechanism of improvement were examined using X-ray diffractometry (XRD), thermal gravimetry (TG-DTG), and scanning electron microscopy (SEM) observations. The results are as follows: (1) The curing of cement was accelerated concomitantly with the improvement in mechanical and dimensional properties of CBP significantly by curing with gaseous or supercritical carbon dioxide. (2) Supercritical carbon dioxide curing imparted boards optimal properties at a faster rate than did gaseous curing. (3) Accelerated formation of calcium silicate hydrate and calcium carbonate and the interlocking of those hydration products on the wood surface are potentially the main reasons for the superior strength of carbon dioxide-cured boards.     

Landscape-scale variation in the structure and biomass of the hill dipterocarp forest of Sumatra: Implications for carbon stock assessments

One of the first steps in estimating the potential for reducing emissions from deforestation and forest degradation (REDD) initiatives is the proper estimation of the carbon components. There are still considerable uncertainties about carbon stocks in tropical rain forest, coming essentially from poor knowledge of the quantity and spatial distribution of forest biomass at the landscape level.     

Response of climate-growth relationships and water use efficiency to thinning in a Pinus nigra afforestation

Thinning is the main forestry measure to increase tree growth by reducing stand tree density and competition for resources. A thinning experiment was established in 1993 on a 32-year-old Pinus nigra Arn. stand in central Spain. The response of growth, climate-growth relationships and intrinsic water use efficiency (WUEi) to a stand density reduction were compared between moderate thinned plots and a control plot by a combined analysis of basal area increments (BAI), and C and O stable isotope ratios (δ¹³C_c and δ¹⁸O_c). BAI in the control plot showed a decreasing trend that was avoided by thinning in the thinned plot. Thinning also partially buffered tree-ring response to climate and trees were less sensitive to precipitation although more sensitive to temperature. Δ¹³C_c in the thinned plot was not modified indicating that stomatal conductance (g) and photosynthetic capacity (A) did not change or change in the same direction. However, δ¹⁸O_c decreased in the control plot (unrelated to δ¹⁸O of precipitation) but not in the thinned plot, suggesting a relative increase of temperature and irradiance and/or a decrease of air humidity after reducing the density consistent with an increase in A, g and BAI. As WUEi did not increase in the thinned plot, faster growth in this plot was caused by higher abundance of resources per tree. The trend of WUEi in both plots indicated low-moderate CO₂-induced improvements. Thinning might be a useful adaptation measure against climate change in these plantations reducing their vulnerability to droughts. However, because WUEi was not affected, the positive growth response might be limited if droughts and warming continue and certain thresholds are exceeded.     

Carbon budget of Ontario's managed forests and harvested wood products, 2001–2100

Forest and harvested wood products (HWP) carbon (C) stocks between 2001 and 2100 for Ontario's managed forests were projected using FORCARB-ON, an adaptation of the U.S. national forest C budget model known as FORCARB2. A fire disturbance module was introduced to FORCARB-ON to simulate the effects of wildfire on C, and some of the model's C pools were re-parameterized using data from Canadian forests. Forest C stocks were estimated using allometric equations that represent the relationships between C and net merchantable volume and forest age based on forest inventory statistics. Other pools were included using results from ecological studies related to forest inventory variables. Data from future forest development projections adopted in approved management plans were used as model input to produce forest C budgets for the province's Crown forest management units. The estimates were extended to other types of managed forests in Ontario: parks, measured fire management zones, and private forest lands. Carbon in HWP was estimated in four categories: wood in use, wood in landfill, wood burned for energy, and C emitted by wood decomposition or burning without energy generation. We projected that the C stocks in Ontario's managed forests and HWP (in use and in landfills) would increase by 465.3 Mt from 2001 to 2100, of which 47.9 Mt is from increases in forest C and 417.4 Mt is from HWP C.     

A comparison of alternative modelling approaches to evaluate the European forest carbon fluxes

The European forest carbon balance studied by various methods shows different results. We compared the regional and national net primary production (NPP) estimated by the forest inventory-based model EFISCEN and the climate-based terrestrial ecosystem models (TEMs: BIOME-BGC, ORCHIDEE, and JULES), and single forests NPP derived from the international network of eddy-covariance towers (FLUXNET). In addition, the paper presents the net ecosystem production (NEP) and the net biome production (NBP) calculated with EFISCEN and discusses the influence of forest management onto carbon fluxes. We aimed to better understand the variance between EFISCEN and TEMs NPP estimates, and to improve the assessment of European forest mitigation potential for the year 2005.     

Carbon dioxide exchange of a larch forest after a typhoon disturbance

A typhoon event catastrophically destroyed a 45-year-old Japanese larch plantation in southern Hokkaido, northern Japan in September 2004, and about 90% of trees were blown down. Vegetation was measured to investigate its regeneration process and CO₂ flux, or net ecosystem production (NEP), was measured in 2006–2008 using an automated chamber system to investigate the effects of typhoon disturbance on the ecosystem carbon balance. Annual maximum aboveground biomass (AGB) increased from 2.7 Mg ha⁻¹ in 2006 to 4.0 Mg ha⁻¹ in 2007, whereas no change occurred in annual maximum leaf area index (LAI), which was 3.7 m² m⁻² in 2006 and 3.9 m² m⁻² in 2007. Red raspberry (Rubus idaeus) had become dominant within 2 years after the typhoon disturbance, and came to account for about 60% and 50% of AGB and LAI, respectively. In comparison with CO₂ fluxes measured by the eddy covariance technique in 2001–2003, for 4.5 months during the growing season, the sum of gross primary production (GPP) decreased on average by 739 gC m⁻² (64%) after the disturbance, whereas ecosystem respiration (RE) decreased by 501 gC m⁻² (51%). As a result, NEP decreased from 159 ± 57 gC m⁻² to −80 ± 30 gC m⁻², which shows that the ecosystem shifted from a carbon sink to a source. Seasonal variation in RE was strongly correlated to soil temperature. The interannual variation in the seasonal trend of RE was small. Light-saturated GPP (P_max) decreased from 30–45 μmol m⁻² s⁻¹ to 8–12 μmol m⁻² s⁻¹ during the summer season through the disturbance because of large reduction in LAI.     

Diurnal and seasonal variations in carbon fluxes in bamboo forests during the growing season in Zhejiang province,China

Bamboo forest is an important forest type in subtropical China and is characterized by fast growth and high carbon sequestration capacity. However, the dynamics of carbon fluxes during the fast growing period of bamboo shoots and their correlation with environment factors are poorly understood. We measured carbon dioxide exchange and climate variables using open-path eddy covariance methods during the 2011 growing season in a Moso bamboo forest(MB, Phyllostchys edulis) and a Lei bamboo forest(LB, Phyllostachys violascens) in Zhejiang province,China. The bamboo forests were carbon sinks during the growing season. The minimum diurnal net ecosystem exchange(NEE) at MB and LB sites were-0.64 and-0.66 mg C m^-2 s^-1, respectively. The minimum monthly NEE, ecosystem respiration(RE), and gross ecosystem exchange(GEE) were-99.3 ± 4.03, 76.2 ±2.46, and^-191.5 ± 4.98 g C m^-2 month^-1, respectively,at MB site, compared with-31.8 ± 3.44, 70.4 ± 1.41,and^-157.9 ± 4.86 g C m^-2 month^-1, respectively, at LB site. Maximum RE was 92.1 ± 1.32 g C m^-2 month^-1 at MB site and 151.0 ± 2.38 g C m^-2 month^-1 at LB site.Key control factors varied by month during the growing season, but across the whole growing season, NEE and GEE at both sites showed similar trends in sensitivities to photosynthetic active radiation and vapor pressure deficit,and air temperature had the strongest correlation with RE at both sites. Carbon fluxes at LB site were more sensitive to soil water content compared to those at MB site. Both onyear(years when many new shoots are produced) and offyear(years when none or few new shoots are produced)should be studied in bamboo forests to better understand their role in global carbon cycling.