Indexing of spatial patterns of trees using a mean of angles

The assessment of information relating to the spatial patterns of individual trees is becoming an increasingly important aspect of forest research and practical forestry. Numerous methods have been proposed over the years, with foresters preferring rapid methods able to provide statistically confident information. The Mean of Angles is one of the simplest of these methods. It is applicable for revealing complete spatial randomness (CSR) or the presence of clustering or regularity. We have tested the potential of the arithmetic mean of angles to serve as a practical measure of the degree of regularity or clustering. This study was conducted by applying random point sampling in various simulated theoretical point populations. The Mean of Angles method deserves consideration as a practical option for examining the spatial patterns of trees in forests. We suggest that the arithmetic mean of angles cannot be completely relied upon for indexing spatial patterns, but this deficiency can be overcome by examining the frequency distributions of angular measurements.     

Comparative Advantages of Small-Scale Forestry Among Emerging Forest Tenures

Forestland tenure institutions and patterns are in a period of rapid change in the USA. Historically dominant forestland tenures are disappearing, and new tenures are emerging. Traditional, vertically integrated forest products firms have shed their forestland holdings which have been picked up by Timber Investment Management Organizations (TIMOs) and Real Estate Investment Trusts (REITs). Increasing numbers of private individuals and families are purchasing small rural tracts and some communities are developing innovative means to gain control over nearby forestlands in order to protect these lands from commercial real estate development. Within this context of rapid ownership change, small-scale forest owners including families and communities find themselves at a competitive disadvantage, relative to large corporate owners, in wood commodity markets. This paper considers how small-scale forest tenures, relative to large corporate tenures, may be advantageous to society with regard to selected ecological, social, and economic factors. While the paper primarily draws upon illustrations from the US Pacific Northwest, its themes are global in nature.     

Application of the amount of oxygen consumption to the investigation of the oxidation mechanism of lignin during oxygen-alkali treatment

The dioxygen consumption by kraft lignin and several lignin model compounds during oxygen-alkali treatments were directly analyzed using a dioxygen fl owmeter. The average dioxygen consumption by 200 g of kraft lignin was about 3 moles. Because this value was as much as those obtained for monomeric phenolic lignin model compounds, guaiacol and vanillyl alcohol, it was postulated that not only phenolic but also nonphenolic moieties in kraft lignin are extensively oxidized. The dioxygen consumption by 0.5 moles (one equivalent of aromatic units) of a dimeric lignin model compound, guaiacylglycerol-β-guaiacyl ether (GG), was also similar to that for 1 mole of guaiacol and vanillyl alcohol, regardless of the type of the aromatic moiety, which supports the above postulation. The most plausible mechanism for the oxidation of nonphenolic moieties is the oxidation of side chains of residual β-O-4 substructures by active oxygen species. By this mechanism, nonphenolic moieties in kraft lignin and GG are converted into corresponding phenolic moieties, and the oxidation by dioxygen progresses. Part of this article was presented at the 13th International Symposium on Wood, Fiber, and Pulping Chemistry (13th ISWFPC), Auckland, New Zealand, May 2005     

Establishment and Management of Fine Clones Cutting Orchard of Camellia oleifera

近年来,油茶产业迅速升温,良种苗木的缺乏制约了油茶产业的发展,其中良种壮苗和适地适树适种源,特别是良种采穗圃建设与管理是关键因素.文章综述了油茶优良无性系采穗圃品种配置方法、营建、管理、采穗以及建档等.     

How are Swedish Forest Owners’ Associations Adapting to the Needs of Current and Future Members and Their Organizations?

This paper examines how Swedish forest owners’ associations are adapting their strategies to fit the changing needs of current and future members, and assesses how this development affects the organizations’ profile and relationship with members. To explore this issue eight semi-structured, face-to-face interviews with chairmen and senior managers from three associations and the Federation of Swedish Family Forest Owners were performed. Results showed that associations have identified an increasing need for management-support activities among members due to their decreasing familiarity with the basics of forestry. Help is increasingly needed both for setting up goals and objectives for their forest ownership, and to practically manage their properties. The associations’ education programmes are also being improved and adapted to suit members’ varying understanding of forestry by the introduction of A-, B- and C-level courses. Education campaigns have proved to be a successful tool for affecting members’ management objectives. Further, the associations see an increasing need for political activity to counter calls for stricter management regulations being made by the media, politicians and environmental organizations and thereby protect members’ ownership rights. Initiatives within the organizations for more efficient governance processes and the professionalization of working procedures within the member organizations may, however, come to reduce individual member involvement in the associations. Members may thus increasingly come to act as customers of service in their interaction with the organizations.     

Antioxidant properties of monomeric,oligomeric, and polymeric fractions in hot water extract from <Emphasis Type="Italic">Pinus radiata</Emphasis> bark

Hot water extract (HWE) from Pinus radiata bark was fractionated into monomeric polyphenol (MPP), oligomeric proanthocyanidin (OPA), and polymeric proanthocyanidin (PPA) fractions by monitoring the UV-visible spectrum of the eluted fractions. Nine polyphenols were identified in MPP: three phenolic acids and six flavonoids. The major compounds of MPP were taxifolin (456 μg/mg), catechins (240 μg/mg), and protocatechuic acid (46.2 μg/mg). The OPA components ranged from dimers to hexamers. PPA comprised procyanidin (PC, 94%), a small amount of prodelphinidin (PD, 6%), and also the higher trans configuration, rather than the cis configuration, of C2-C3. The average molecular weight (Mw, Mn), polydispersity (Mw/Mn), and DP of PPA were 3,800 (Mw), 1,200 (Mn), 3.2 and 13, respectively. The potential antioxidant activities of HWE and the three fractions were estimated using proton- or electron-donating assays containing 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radical cation, superoxide anion (O₂^•−), hydrogen peroxide (H₂O₂), reducing power and lipid peroxidation. All the bark fractions exhibited potent quenching abilities against both commercially available radicals (DPPH•, ABTS^•+) and chemically induced radicals (H₂O₂, O₂^•−), as well as strong reducing power and inhibitory activity of lipid peroxidation. Particularly, OPA showed a hydrogen peroxide scavenging activity significantly higher (p < 0.05) than that of the other fractions. From 2-thiobarbituric acid reactive substances and ferric thiocyanate assays, PPA was suspected to act by essentially delaying the formation of hydroperoxide by quenching free oxygen radicals that operates in oil-in-water emulsion.     

Prediction of internal bond strength in a medium density fiberboard process using multivariate statistical methods and variable selection

This paper presents new data mining-based multivariate calibration models for predicting internal bond strength from medium density fiberboard (MDF) process variables. It utilizes genetic algorithms (GA) based variable selection combined with several calibration methods. By adopting a proper variable selection scheme, the prediction performance can be improved because of the exclusion of non-informative variable(s). A case study using real plant data showed that the calibration models based on the process variables selected by GA produced better performance than those without variable selection, with the exception of the radial basis function (RBF) neural networks model. In particular, the calibration model based on supervised probabilistic principal component analysis (SPPCA) yielded better performance (only when using GA) than partial least squares (PLS), orthogonal-PLS (O-PLS), and radial basis function neural networks models. The SPPCA model benefits most from the use of GA-based variable selection in this case study. N. André and H.-W. Cho equally contributed to this work.     

Carbon inventory methods and carbon mitigation potentials of forests in Europe: a short review of recent progress

The role of European forests and forest management in the carbon balance has received much attention in research recently. This was particularly motivated by the recognition of forest management as one possible measure countries may adopt in the framework of the Kyoto Protocol to reduce the concentration of greenhouse gases in the earth’s atmosphere. The main method to assess carbon budget in forests is based on traditional forest inventories. This method requires the conversion of measured stem volume to carbon pools. This conversion has been identified as a large source of uncertainty in past assessments. Over the last 5 years, intensive research efforts have resulted in significant advances in the reliability of forest inventory based carbon budgets. In parallel, the impact of forest management on the carbon balance of forest ecosystems has been investigated and the carbon mitigation potential of these activities has been analysed. This paper reviews the progress that was made in these two fields of research with a particular focus on European forests.

原竹对剖联丝展开重组技术的推广

阐述了原竹对剖联丝展开重组技术的工艺流程,指出新工艺减少了加工工序,提高了竹材利用率和竹青面耐磨性,降低了生产成本;从原竹对剖联丝展开重组技术制备的层积材性能与特点,分析了新工艺的创新点,并从经济效益和社会效益两点分析了新技术的可行性。重组技术的推广应用,竹制品行业将大大提高竹材利用率,降低生产成本,实现产品换代升级,企业更具有生命力。