22 research outputs found
Differences in branch characteristics of Scots pine (Pinus sylvestris L.) genetic entries grown at different spacing
• We studied the differences in branch characteristics along the stems of six different
genetic entries of 20 year old Scots pines (Pinus sylvestris L.) grown at
different spacing (current stand density range 2000–4000 trees ha−1) in central
Finland. Furthermore, we studied the phenotypic correlations between yield, wood density
traits and branch characteristics. All the genetic entries had Kanerva pine (plus tree
S1101) as a father tree, whereas the mother tree represented Finnish plus trees from
southern, central and northern Finland.
• Spacing affected all yield traits, wood density and living branch characteristics such
as relative average branch diameter and relative cumulative branch area
(p < 0.05). As a comparison, genetic entry affected height,
while origin group (southern, central and northern ones) affected most of the studied
traits. Regardless of spacing, the northern origin had, on average, the largest stem
diameter and highest wood density, while the central one was the tallest one. Furthermore,
average branch diameter along the stem was affected by branch age, origin group and
spacing, while average branch angle was affected by branch age and genetic entry
(p < 0.05).
• In general the average branch size could be decreased especially in lower tree canopy
by denser spacing during the early phase of the rotation, but only at the expense of tree
growth. Correspondingly differences between origins are mainly related to their
differences in stem growth
Effects of genetic entry and competition by neighbouring trees on growth and wood properties of cloned Norway spruce (Picea abies)
• The aim of this work was to study both the effects of genetic entry and competition by
neighbouring trees on growth, yield, wood density traits and fibre properties of 20 Norway
spruce clones grown in an experimental trial located in southern Finland. The material
included 10 Finnish clones, 2 Russian clones and 8 provenance-hybrids clones, the latter
ones representing crosses between Finnish and foreign parent trees.
• We found that,
compared to growth and yield, wood density traits and fibre properties showed, on average,
lower phenotypic variations. Moreover, significant differences could be observed among the
clones regardless of the trait (p < 0.05). Conversely, on average,
no clear differences could be found between Finnish, Russian and provenance-hybrids clones
in most of the studied traits.
• The marked differences among the clones, and lack of clear
differences among the provenances suggested that any ranking, regarding different traits,
should be based on individual clones. The phenotypic correlations between different traits
ranged from moderate to strong suggesting that selection based on one trait would affect
other traits. Regardless of clone, the growth of trees (e.g. breast height diameter)
decreased and the wood density increased with increasing competition by neighbouring
trees, which was expressed by competition index
Differences in wood decay by Heterobasidion parviporum in cloned Norway spruce (Picea abies)
Effects of cambial age, clone and climatic factors on ring width and ring density in Norway spruce (Picea abies) in southeastern Finland
Stand, tree and crown variables affecting cone crop and seed yield of Aleppo pine forests in different bioclimatic regions of Tunisia
Variables de parcela, arbol y copa que afectan la produccion de piñas y piñones en bosques de pino carrasco de Tunez
In Tunisia, the Aleppo pine seed has a great importance, since in the last decades human consumption has risen
considerable. Thus its regeneration and seed production capacities are important factors to take into account to reach
the necessities of the country. To study the production of cones and seeds of Aleppo pine, Tunisia’s native Aleppo pine
forests were surveyed in summer 2006, using 79 plots (40 × 25 m: 1,000 m²) spread over four bioclimatic zones. Stand
and tree characteristics, crown dimensions and cone/seed variables were measured from an average tree of each plot
(i.e. a total of 79 trees). Recorded data were submitted to simple and multiple regression analyses for explaining the
variability in crown volume and crown surface, cone number and seed yield per average tree. Results showed a negative
correlation between the stand density, crown characteristics and number of cones and seeds harvested from the
average tree. For crown volume and surface, age, stand density, tree height, diameter at breast height, crown diameter
and crown height were important explanatory variables under multiple regression analyses. For cone number per tree,
only the age, stand density and total height were the most determinant variables. Matures cone number per tree and
cone mass per tree were the most informative parameters for the total seed yields per tree. Finally, forest managers
should know that crown size affects cone and seed crop of the Aleppo pine individual tree grown in Tunisia, but has
no effects on seed number per cone and seed mass per cone
A decision support system for management planning of Eucalyptus plantations facing climate change
International audience& Context Climate change studies in Portugal point to warming winters and increase in the dry season length, impacting growth of plants. New tools are needed to increase the effectiveness of forest management planning under climate change. & Aims To develop research tools that may help forest managers cope with climate change challenges to long-term planning. These tools should help assess the impact of climate change on the timing and location of forest management options as well as on forest products flows. & Methods The proposed tools are based on information system architecture approaches that suggested a "Decision Support System" (DSS) with a modular structure to integrate (1) a management information module; (2) a prescription generator module that integrates a process-based model (Glob3PG); (3) a decision module; (4) a solution report module. To demonstrate the usefulness of the DSS, a eucalyptus forest with 1,722 stands (6,138 ha) in Portugal was considered. Two climate scenarios were used. & Results Potential wood supply decreased from 2.35 to 2.19 million m 3 , land value depreciated from 81.1 to 74.7 million Euro and total carbon stock decreased from 228 to 212 tons. & Conclusions The DSS demonstrated that the design of optimal management plans should take into account climate change
Effects of spacing and genetic entry on radial growth and ring density development in Scots pine (Pinus sylvestris L.)
Effects of thinning and pruning on stem and crown characteristics of radiata pine (Pinus radiata D. Don)
Simultaneous applications of thinning and pruning are common silvicultural practices in radiata pine (Pinus radiata) forest plantations. Their separate effects on tree growth and wood quality have been well studied, but their combined effect is not clear yet. The aim of this study is to identify how thinning and pruning together affect the stem structure and properties of the pruned but also the unpruned section of the trees (the portions formed immediately after the application of these management efforts). The effects of pruning and thinning on the number of growth units per year, internode length, number of branches, and branch diameters was analyzed in managed and unmanaged stands of radiata pine grown in Chile. When used jointly, these practices generated larger individual tree volumes (135% more) and clear wood in the pruned logs; however, they also reduced the sawn wood quality of the unpruned stem section for some years after the silvicultural interventions. The managed trees showed more growth units per annual shoot and shorter internodes, thus generating more knotty wood. Moreover, managed trees showed more taper. As trees of the managed stand restore the foliar biomass lost due to pruning, managed and unmanaged stands approach the same level of canopy closure, and differences minimize