Evaluating Carbon Stock Changes in Forest and Related Uncertainty

For the evaluation of changes in the carbon stock of living biomass, two methods are reported in the Good Practice Guidance for Land Use, Land-Use Change, and Forestry: (1) the default method, which requires the biomass carbon loss to be subtracted from the biomass carbon increment for the reporting year; and (2) the stock change method, which requires two consecutive biomass carbon stock inventories for a given forest area at two points in time. We used three methods to estimate above-ground biomass: (1) application of allometric equations, (2) constant BEF (biomass expansion factor), and (3) age-dependent BEF, following which we evaluated the changes in carbon stock and the related uncertainty. Our study was carried out in a Douglas fir plantation composed of plots with three different planting densities, monitored at three different ages (15, 25, and 40 years old). Results showed the highest uncertainty in the estimates based on the constant BEF, whereas the use of allometric equations led to the lowest uncertainty in the estimates. With a constant BEF, it is usually difficult to obtain a reliable value for the whole tree biomass because stem proportion increases with tree size at the expense of the other components. The age-dependent BEFs aim to reduce the bias representing the actual change in stock, thus we found a lower uncertainty in the estimates by using this method compared to the constant BEF. The default method had the highest uncertainty (35.5–48.1%) and gave an estimate higher by almost double compared to the stock change method, which had an uncertainty ranging from 2.9% (estimated by the allometric equation) to 3.4% (estimated by the constant BEF)

Experimental research in ageing holm oak (Quercus ilex L.) coppices: preliminary results

The initial data of a long-term research programme aimed at determining the silvicultural choices for management of ageing holm oak coppices are reported. The various treatments being tested are the following: treatments A and B, respectively, with 50 and 250 reserve trees per hectare, all of the same age; treatment C with 140 reserve trees per hectare, with three different ages; treatment D, conversion into high forest; and treatment E, natural evolution (the control). A total of 15 permanent plots were established (five treatments x three replicates) and the experimental design used is that of randomized blocks. The results presented regard the structural development of the coppice during the first 2 years after coppicing. Regeneration from seed showed a significant correlation with treatment. Data relative to the characteristics of the stands existing before the various interventions also are given. Such preliminary results need further periodical observations. (© Inra/Elsevier, Paris.)Expérimentation concernant les taillis vieillis de chêne vert (Quercus ilex L) : premiers résultats. Les résultats obtenus et ici présentés font partie d'un projet de recherche dont l'intention est d'individualiser des possibles options de culture pour les taillis de chêne vert vieillis. On a confronté les cinq thèses suivantes (avec trois répétitions) : les thèses A et B avec respectivement 50 et 250 réserves par hectare ayant toutes le même âge ; la thèse C avec 140 réserves par hectare, ayant trois âges différents ; la thèse D, conversion en futaie ; la thèse E, évolution naturelle. Les résultats exposés concernent l'évolution du peuplement pendant les deux premières années du cycle productif. Pour ce qui concerne la regénération, la présence des semis semble être favorisée par un couvert pas trop excessif des réserves. Il s'agit malgré tout de résultats préliminaires qui dérivent de parcelles d'échantillonage permanentes où, chaque année, on réalisera des reliefs. (© Inra/Elsevier, Paris.

Assessing the current status of urban forest resources in the context of Parco Nord, Milan, Italy

During the early part of the 1980s, a major project called Parco Nord was undertaken by the Lombardia Region to establish forest resources within an industrial area located in the northern part of the city of Milan. Since 1983, more than 60 ha of formerly industrial land has been converted into urban forest plantations, thus creating large patches of trees with the potential to sustain a wide range of functions and services. This paper describes an integrative study aimed to assess the current status of forest resources in Parco Nord. It focuses on the actions taken to determine whether forest resources significantly changed their status 20 years after their establishment, considering historical field data and records of management practices. Analyses have been conducted at both stand and tree level by collecting quantitative and qualitative parameters. Stand-level analysis gave a quantitative estimation of the response of species to ecological conditions and management practices while tree-level analysis provided evidence of species renovation after thinning operations. © 2007 International Consortium of Landscape and Ecological Engineering and Springer.Link_to_subscribed_fulltex

Root system investigation in sclerophyllous vegetation: An overview

Sclerophyllous vegetation contributes to the formation of forest resources in the Mediterranean biome that in turn provides an important resource in terms of ecosystem services. Despite this, scientific knowledge of sclerophyllous vegetation, in particular with regard to their root systems, is fragmented. This review takes into account the research on below-ground sclerophyllous biomass in different contexts where there is a Mediterranean climate. In particular, the authors analyse the different investigative approaches used in studying roots, the main topics covered by research, and the relationships between root and shoot biomass. The review shows that there is a paucity of research on the root systems of sclerophyllous vegetation although there are examples of innovative technologies being applied to research questions. This review considers some key works in the literature, and provides useful information to address re-vegetation and reforestation programmes in the context of Mediterranean ecosystems. © G. Sanesi et al., 2013 Licensee PAGEPress, Italy.Link_to_subscribed_fulltex

Structural diversity and height growth models in urban forest plantations: A case-study in northern Italy

Current knowledge on the growth models of urban forest plantations several years after their establishment still remains poor and fragmentary. Furthermore few studies have assessed the growth of urban plantations on reclaimed land, such as brownfield sites. This paper assesses urban forest plantations in terms of tree height growth, crown width and vertical structural using as a case study tree inventory-data collected in an urban forest plantation (Parco Nord Milano, PNM northern Italy). In this research tree inventory-dat a was used to achieve the following objectives: (i) to develop a series of tree height-growth models and tree crown-width models for the main taxonomic units in the study-area; (ii) to analyse the temporal pattern of current increments of tree height; (iii) to assess the vertical stratification of tree crowns using a method developed by Latham et al. (1998). The results suggest that during the earlier stage after planting, trees reach high levels of growth (tree height and crown width) regardless of the taxonomic unit. Evidence is found to support a high level of spatial competition between individual trees of different taxonomic units in as little as 15-18 years. Competition between trees appears to be mainly affected by diametrical differentiation rather than hypsometric variation: trees grow more in diameter than in height. Furthermore a decrease in longitudinal growth was observed for most tree species while the radial growth tends to be constant over time. The research at PNM shows that in temperate climates this can be achieved in less than 30 years. We believe that these analyses could provide important data supporting the planning of new urban forest plantations on reclaimed land and inter alia provide some answers to the questions around plantations growth evaluation and management. © 2013 Elsevier GmbH.Link_to_subscribed_fulltex

Biomass conversion and expansion factors in Douglas-fir stands of different planting density: variation according to individual growth and prediction equations

Aim of study: We built biomass expansion factors (BCEFs) from Douglas-fir felled trees planted with different planting densities to evaluate the differences according tree size and planting density.Area of study: The Douglas-fir plantation under study is located on the northern coastal chain of Calabria (Tyrrhenian side) south Italy.Materials and methods: We derived tree level BCEFs, relative to crown (BCEFc), to stem (BCEFst = basic density, BD) and total above-ground (BCEFt) from destructive measurements carried out in a Douglas-fir plantation where four study plots were selected according to different planting densities (from 833 to 2500 trees per hectare). The measured BCEFs were regressed against diameter at breast height and total height, planting density, site productivity (SP) and their interactions to test the variation of BCEFs. Analysis of variance (ANOVA) and the post hoc Tukey comparison test were used to test differences in BCEFt, BCEFc and in BD between plots with different planting density.Main results: BCEFs decreased with increasing total height and DBH, but large dispersion measures were obtained for any of the compartments in the analysis. An increasing trend with planting density was found for all the analyzed BCEFs, but together with planting density, BCEFs also resulted dependent upon site productivity. BCEFt average values ranged between 1.40 Mg m-3 in planting density with 833 trees/ha (PD833) to 2.09 Mg m-3 in planting density with 2500 trees/ha (PD2500), which are in the range of IPCC prescribed values for Douglas-fir trees.Research highlights: Our results showed that the application of BCEF to estimate forest biomass in stands with different planting densities should explicitly account for the effect of planting density and site productivity