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1.
油茶象危害油茶果实的初步研究 总被引：3，自引：1，他引：2
对福建省闽侯桐口国有林场油茶杂交试验林果实的果径、果高、果重、籽重(种仁重)以及果实受害率等进行测定,分析油茶象对油茶果的危害情况。结果表明:在调查的油茶林分中,株受害率为94.7%,平均虫果率为14.7%;健康果平均果径为3.01 cm,显著地大于虫果的2.86 cm;健康果平均果高为3.05 cm,显著地高于虫果的2.84 cm;健康果平均果重为16.8 g.个-1,极显著地大于虫果的果重;健康果籽重为6.2 g.个-1,极显著地大于虫果籽重4.8 g.个-1;结果表明:油茶象的危害严重影响了油茶果的生长和油茶的产量。 相似文献
2.
Big-leaf mahogany (Swietenia macrophylla) trees are often retained in agricultural fields and pastures for seed and timber production after selective logging and
forest clearing in the Brazilian Amazon. At a forest management site in southeast Pará, we censused trees growing scattered
across a large open clearing after forest removal and in heavily disturbed forest after selective logging and canopy thinning
for survival, stem diameter growth, fruit production, and date of dry season flowering initiation annually during 1997–2003.
Trees in the open clearing died at faster rates, grew more slowly, produced fewer fruit, and initiated flowering earlier,
on average, than trees in logged and thinned forest during this period. The principal cause of mortality and stem damage in
both environments was dry season groundfires. Mahogany trees in logged and thinned forest at the study site grew faster than
mahogany trees at a selectively logged but otherwise undisturbed closed-canopy forest site in this region during the same
period. This was likely due to vine elimination by groundfires, increased crown exposure after canopy thinning, and soil nutrient
inputs due to groundfires. Without effective regulation and control of anthropogenic fires, attempts to manage remnant mahogany
trees for future timber yields or to restore commercially viable populations in this region may prove futile. 相似文献
3.
The fruit of Vitellaria paradoxa is an ideal raw material in cosmetic, pharmaceutical and confectionery industries. There are no accurate data on annual fruit yield due to the lack of objective assessment tools. The objectives of this study were to develop fruit yield prediction models based on dendrometric and fruiting variables, to examine variations in these variables between upland and lowland populations in Burkina Faso, and associations between these variables. A total of 191 fruiting trees were selected according to crown accessibility, and 17 dendrometric and fruiting variables were recorded. The fruit yield, expressed in number of fruits per tree, fresh and dry weights of fruits, was assessed by collecting fruits dropped overnight until the end of the fruiting period. Fruit yield prediction models were derived for each population using partial least squares regression. The results showed significant differences in dendrometric and fruiting variables between populations (P < 0.01). The lowland population had the highest values for most of the dendrometric variables while fruiting variables were the highest for the upland population. A strong significant correlation (P < 0.01) was found between number of shoots and fruiting variables. Within individual trees, fruit yield was lowest for the bottom part of the crown and the section of the crown with north-east orientation. Fruit yield parameters were successfully predicted based on selected dendrometric and fruiting variables (prediction error = 0.092 and 0.125 for upland and lowland populations, respectively). All fruiting variables, number of shoots and crown attributes had the highest influence on the models. 相似文献
4.
According to the new trend of insect pests control in fruit orchards, biological in addition to mechanical control were evaluated
for their efficiency on the reduction ofP. paradoxa population on fig trees during 1996, 1997 and 1998. Primary trials using the bacterial biopreparations of Delfin, Dipel and
Bactospeine at the concentration of 200g/100 l. w. resulted in 81.8, 75.8 and 72.3% reduction of pest infestation, respectively.
Pruning the infested branches, worming the larvae inside their tunnels and both mechanical treatments together along two successive
years, reduced the infestation by 17.5, 47.4 and 57.9%, respectively. A control programme ofP. paradoxa was conducted using the techniques of pruning and worming besides spraying with bacterial insecticides at a rate of 200g/100
l.w. The performed mechanical and biological treatments together for one year gave 79.2–94.5% reduction of infestation, that
reduction increased to 83.0–98.1% when these treatments were applied two years successively. 相似文献
5.
P.O. Anegbeh C. Usoro V. Ukafor Z. Tchoundjeu R.R.B. Leakey K. Schreckenberg 《Agroforestry Systems》2003,58(3):213-218
Domestication of Irvingia gabonensis, a fruit tree grown in agroforestry systems in West and Central Africa, offers considerable scope for enhancing the nutritional
and economic security of subsistence farmers in the region. Assessments of phenotypic variation in ten fruit, nut and kernel
traits were made on twenty-four ripe fruits from 100 Irvingia gabonensis trees in Ugwuaji village in southeast Nigeria, a center of genetic diversity for this species. There were important differences
between the young planted trees of this study and the older unplanted trees of a similar study in Cameroon. Significant and
continuous tree-to-tree variation was found in fruit mass(69.0–419.8 g), flesh mass (59.5–388.8 g), nut mass (9.5–40.6 g),
shell mass (4.9–30.9 g) and kernel mass (0.41–7.58 g); fruit length (49.2–89.3 mm) and width (46.2–100.5 mm) and flesh depth
(12.9–31.4 mm), as well as considerable variation in flesh colour, skin colour, fruit taste and fibrosity. Some fruits were
considerably bigger than those found in Cameroon. These quantitative results will help in the development of cultivars within
participatory approaches to agroforestry tree domestication, and so promote poverty alleviation and sustainable agriculture.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
6.
Arazá (Eugenia stipitata), a fruit shrub originating from Western Amazonia, was evaluated growing in association with timber shade trees (Acacia mangium or Cordia alliodora) or with plantain (Musa sp.) as a potential commercial species for the tropical moist lowlands of Talamanca, Costa Rica. Height and crown width of
the four-year-old shrubs varied between 2.7–2.8 m and 2.9–3.1 m, respectively. Flowering was positively correlated with initial
fruit formation 1 month later and initial fruit formation with fully developed fruits a subsequent month after that. Three
to four-year-old plants produced 20.0, 20.0, and 24.5 t ha−1 yr−1 (fresh fruits) in associations with A. mangium, C. alliodora and plantain, respectively, with higher production in rainy months. Fruit production in later years under C. alliodora (six to eight-year-old shrubs) was 26.5 t ha−1 yr−1. Where markets exist for E. stipitata fruit, the association can be recommended for tropical humid lowlands of Central America. 相似文献
7.
A.R. Atangana V. Ukafor P. Anegbeh E. Asaah Z. Tchoundjeu J.-M. Fondoun M. Ndoumbe R.R.B. Leakey 《Agroforestry Systems》2002,55(3):221-229
Ten fruit and kernel traits were assessed in 24 fruits of each of 152Irvingia gabonensis trees in three distinct populations in west and central Africa [2 populations of non-planted trees in Cameroon: Nko'ovos
II (21 trees) and Elig-Nkouma (31 trees) and 1 population of planted trees in Nigeria: Ugwuaji (100 trees)]. Strong relationships
were found between fruit weight and other fruit traits (e.g. flesh weight[r
2 = 0.99: P < 0.001],fruit length [r
2 = 0.74–0.83:P < 0.001], fruit width[r
2 = 0.77–0.88: P< 0.001]). In contrast, relationships between kernel weight and other kernel/nut traits (e.g. shell weight and nut weight)
were found to be weak[r
2 = 0.009–0.37, P =0.058–0.001], with the exception of nut weight at Nko'ovos II(r
2 = 0.65, P < 0.001).Relations hips between fruit and kernel traits (fruit massv. kernel mass, fruit mass v. shell mass, flesh mass v. kernel mass, nut massv. fruit mass and flesh depth v.kernel mass) were found to be very weak. This indicates that domestication through the selection and vegetative propagation
of multiple-trait superior phenotypes is unlikely to be able to combine good fruit characteristics and good kernel characteristics
within cultivars. Consequently, domestication activities should independently focus on ideotypes representing: 'fresh fruit'
traits, and 'kernel' traits, that combine high values of the different fruit and kernel characteristics respectively. Evidence
from this study indicates that selection of the three trees closest to the fruit ideotype per village as the mother plants
for vegetative propagation and cultivar development, should give village level gains of 1.3 – 2-fold in fruit mass, and up
to 1.5-fold in taste. Similarly for the kernel ideotype, selection of the three trees with the best fit would give potential
gains in kernel mass of 1.4 – 1.6-fold.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
8.
Nobuaki Ohtaka Hayato Masuya Shigeru Kaneko Yuichi Yamaoka Masashi Ohsawa 《Journal of Forest Research》2002,7(3):145-151
Relationships between tree mortality and bark beetle infestation onAbies veitchii at the wave-regenerated forest in Mt. Asahi, Okuchichibu area were investigated. Most of the firs with green needles and
newly developed current year’s shoots in the dieback zone were heavily infested by bark beetles before the death of the trees.
After heavy infestation of beetles, about half of the infested firs died within the year, and the other half died in the next
year. When the species composition of bark beetles and associated ophiostomatoid fungi were investigated in Mt. Asahi and
also at a typical wave-regenerated forest in Mt. Shimagare, Yatsugatake area,Cryphalus montanus andC. piceae were dominant beetle species for Mt. Asahi and Mt. Shimagare, respectively.Ophiostoma subalpinum andO. europhioides were dominant fungal species at both wave-generated forests. BecauseO. subalpinum was detected more frequently from deeper areas of sapwood thanO. europhioides, it was suggested that the fungal species may accelerate the death of stressed firs in wave-regenerated forests.
Contribution No. 169, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba. 相似文献
9.
I. Kadzere C. B. Watkins I. A. Merwin F. K. Akinnifesi J. D. K. Saka J. Mhango 《Agroforestry Systems》2006,68(2):133-142
Uapaca kirkiana (Muell. Arg.), a highly valued indigenous fruit species, is being domesticated to increase its utilization in southern Africa. Vendors, who were also the fruit gatherers, that were selling U. kirkiana fruits at roadside markets in Dedza, Malawi, were interviewed on four occasions during the marketing season (October 2003–January 2004) and fruit samples were concurrently sampled from each vendor. Information was obtained on when and how the fruits had been harvested and handled. Timing of fruit harvest was based on experience, aided by indicators such as occurrence of first heavy rains, natural abscission, size and color changes. Harvesting by knocking down unripe fruits from trees was practiced throughout the␣season, but naturally abscised fruits were also gathered in December and January. Fruits harvested when mature but unripe required incubation in soil, plain and woven plastic bags or clay-pots. The incubation method changed and the duration of incubation decreased between October (3–4 days) and January (≤2 days). Fruit samples were evaluated for damage, color and soluble solids concentration (SSC). Fruit SSC and color lightness/brightness (L*) increased from 10.1 to 16.4% (P<0.01) and from 45.7 to 50.5 units, (P<0.01), respectively. Higher SSC values were generally associated (R
2=0.68, P<0.001) with increasing pulp color intensity. Cracking, at 48%, constituted the most common form of damage in sampled fruits. On average, fruits were saleable for only 3–4 days, this being attributed to inherent fruit characteristics combined with immaturity at harvest, and damage during harvesting and storage in hot dry conditions. Lack of appropriate harvesting and handling techniques were associated with fruit darkening, drying, rotting and other postharvest problems. 相似文献
10.
In 2010, the first, and so far only, infestation of the Hungarian spruce scale (Physokermes inopinatus) and accompanying sooty mould occurred in Scania, southernmost Sweden. About 1000?ha of Norway spruce (Picea abies) were affected, and the trees suffered from the sucking of the insects as well as from the dense sooty mould that covered the needles. Salvage cuttings were carried out in many of the massively attacked forest stands, both in response to the fear that the trees otherwise would die, e.g. from secondary bark beetle attacks and to prevent spreading of the infestation. The aim of this study was to provide basic, quantitative knowledge on the aftermath response of trees that were heavily infested, but not exposed to salvage cutting. Growth characteristics, in terms of needle weight, shoot length and tree-ring size were measured on infested and uninfested trees to compare and contrast the spruce growth before, during and after the scale outbreak. The infestation resulted in dwarf annual shoots, stunted needles and thin tree rings. The needle weight returned to normal the following year, whereas shoot length and tree rings required one growing season before full recovery. 相似文献
11.
An understanding of the inter-relationships between the traits characterising tree-to-tree variation in fruits and kernels
is fundamental to the development of selected cultivars based on multiple trait selection. Using data from previously characterised
marula (Sclerocarya birrea) trees in Bushbuckridge, South Africa and North Central Region of Namibia, this study examines the relationships between
the different traits (fruit pulp, flesh/juice mass, and nut shell and kernel mass) as a means to determine the opportunities
to develop cultivars. Strong and highly significant relationships were found between fruit mass and pulp mass in trees from
South Africa and Namibia, indicating that size is a good predictor of fruit pulp production. However, fruit size is not a
good predictor of nut or kernel production, as there were weak relationships between fruit and nut and/or kernel mass, which
varied between sites and landuses. Generally, the relationships between fruit mass and kernel mass were weaker than between
fruit mass and nut mass. Relationships between kernel mass and shell mass were generally weak. The lack of strong relationships
between fruit and kernel mass does, however, imply that there are opportunities to identify trees with either big fruits/small
nuts for pulp production, or trees with large kernels in relatively small fruits for kernel oil production. However, within
fruits from the same tree, nuts could contain 0–4 kernels, indicating that even in trees with an inherent propensity for large
kernels, improved pollination may be required to maximise kernel mass through an increase in kernel number. Finally, the relationships
between percentage kernel oil content and the measured morphological traits were also very weak. The conclusions of these
results are that there is merit in identifying different combinations of traits for the selection of trees producing either
pulp or kernels. Consequently, fruit and kernel ‘ideotypes’ are presented as guides to the selection of elite trees for cultivar
development. These results have important implications for the domestication of the species as a producer of fruits or kernels
for food/beverages or cosmetic oils. 相似文献
12.
A non-destructive sampling strategy for basic density, based on removing 12 mm bark-to-bark cores, was developed in E. globulus and E. nitens. Fifty trees of each species, aged 5 to 9 years, were sampled across a range of sites. Core samples were removed on both
a north-south and an east-west axis from 6 fixed heights in the base of the tree (0.5 m, 0.7 m, …, 1.5 m). Whole-tree values
were calculated from disc samples removed at eight percentage heights (0, 10, 20, …, 70%) and correlations between the cores
and whole-tree values were used to determine the optimal sampling height. Core samples were found to be reliable predictors
of whole-tree density, explaining between 84% and 89% of the variation between trees. Core sampling of E. globulus and E. nitens to estimate basic density of whole-trees and stands is feasible; cores from trees at all E. globulus sites gave high correlations with whole-tree values. For E. nitens, site differences were apparent, and it is recommended that a small destructive sampling program should be undertaken prior
to commencing a major sampling program. Recommended optimal sampling heights are 1.1 m for E. globulus and 0.7 m for E. nitens. Core orientation was not important and density was not related to tree size. Six whole-tree samples or eight core samples
are required for estimating the mean density of a stand at a specific site to an accuracy of ±20 kg m−3 with a 95% confidence interval.
Received 17 September 1998 相似文献
13.
We investigated mature dwarf Abies mariesii trees growing in conifer thicket–meadow parklands on a snowy subalpine plateau, where these dwarf trees are buried in the
accumulated snow in winter. We focused on structural variation in the needles, shoots, and branchlets within different crown
positions (leader crown vs lower crown) of the dwarf trees. In the leader crown, which appears above the snow surface earlier
than the lower crown, current-year shoots and branchlets had greater total biomass, and foliage was more closely packed along
the stem axis than in the lower crown, whereas current-year shoots in the leader crown had a lower needle mass ratio than
in the lower crown. These results suggest that current-year shoots and branchlets in the leader crown have a specific structure
that allows them to harvest more light, although construction and maintenance costs would be higher. In contrast, the structural
characteristics of current-year shoots and branchlets in the lower crown efficiently concentrate incoming light by avoiding
mutual shading within foliage, thus leading to increased biomass of photosynthetic needles within shoot and branchlet biomass.
Such within-crown variability at various hierarchical levels from needles to branches in mature, but very dwarf, A. mariesii trees maintains the crown and allows survival within conifer clumps in areas of subalpine parklands that receive heavy snowfall. 相似文献
14.
《Scandinavian Journal of Forest Research》2012,27(1-4):217-226
Population levels of Ips typographus in 8 Danish forest districts were monitored by pheromone traps and baited trees in 1988 and 1989. The number of trees with spontaneous colonization was also registered. All monitoring results were below earlier defined “risk thresholds”;, and accordingly no serious damage was found. Mean catch ranged from 3406 to 12043 beetles per trap group, and induced colonization averaged 1.08 trees per tree‐baiting site. Trie number of colonized trees (total infestation) ranged from 3.5 to 63.2 trees per 100 ha forest. Correlation was found between mean catch and induced colonization (r=0.56), and between induced colonization and total infestation (r=0.65). Accumulated data from 1988–89 and 1984–86 showed good correlation between catch size and number of infested standing trees (r=0.91). From 1988 to 1989 no significant changes occurred, apart from a shift in host material from standing trees to windfalls and timber. I. Typographus monitoring on regional levels is possible also under non‐epidemic conditions. With a limited number of monitoring units, trapping, tree‐baiting and registrations of infestation in exposed edges can give estimates sufficiently accurate to be of practical use to local foresters. 相似文献
15.
Moses Imo 《Agroforestry Systems》2009,76(2):265-273
Lack of empirical data on the effects of the taungya system on establishment and early growth of softwood plantations have partly contributed to controversial decisions regarding
the continued suitability of the system for plantation establishment in Kenya. This study examined effectiveness of taungya systems of forest plantation establishment using Cupressus lusitanica and Pinus patula trees with Zea mays (maize) as a test intercrop on two contrasting site types (deep and shallow soils) in Mt. Elgon forest, western Kenya . Four
treatments were evaluated in each site: trees with or without weed control, trees intercropped with maize, and sole maize.
Results showed that tree survival, growth and nutrient uptake, and maize growth and yield were higher in the deep soil site
than the shallow site. The t
aungya system improved tree survival and growth, effects being greater in the deep than the shallow soil site. Both Cupressus lusitanica and Pinus patula trees had the same effects on maize growth and yield, reducing maize growth by 41–48% in the deep soil sites, and by 16–26%
in the shallow site. Vector nutrient analysis and vector competition analysis of the treatment effects on growth and nutrient
uptake of the trees and the maize crop suggested competition for N on the deep soils, but competition for K and P on the shallow
soils. The study has demonstrated the applicability of graphical vector competition analysis in diagnosing tree–crop interactions
in agroforestry. 相似文献
16.
M. Kozioł 《Journal of pest science》1998,71(7):121-127
A field study onKaltenbachiola strobi (Winnertz) (Diptera: Cecidomyiidae), was carried out between 1987 and 1993 in the highest mountain range in the Western Carpathians
located within the Tatra National Park, in southern Poland. Rearing and analysis of 5 780 cones ofPicea abies (L.)Karst., collected from trees growing at different altitudes, yielded 30,478 individuals ofKaltenbachiola strobi, which infested 89.10% of the cones. In case of 29.81% of cones there were more than 20 larvae ofK. strobi per cone. It was shown thatK. strobi in the Tatra Mts. is more abundant in spruce stands of the upper mountain forest zone. Significant connections between the
time of cone infestation byK. strobi and its parasitoids and characteristic phenophases in spruce foliage and cone development, and also the development of selected
vegetation of the forest floor at different heights above sea level were determined. It was shown that the population dynamics
ofK. strobi had tendency to alternate the increase and decrease in numbers every two years. It was also discovered that every two years
spruce cones were inhabited by the population ofK. strobi with increased percentage of individuals having prolonged diapause. In total, the parasitoids reduced the population ofK. strobi by about 16–22.63%. Parasitism ofK. strobi in the lower mountain forest zone was higher than in the upper zone.Triplatygaster contorticornis
Ratz. (Hymenoptera: Platygasteridae),Torymus azureus
Boheman (Hymenoptera: Torymidae) andTetrastichus strobilanae
Ratz. (Hymenoptera: Eulophidae) were most effiecient in reduction of the population ofK. strobi, and in the lower mountain forest zoneT. azureus was the dominant parasitoid species, while in the upper zoneT. contorticornis andT. strobilanae. It was shown that a considerable part of the populations ofT. azureus, T. contorticornis andT. strobilanae have their diapause prolonged and highly synchronized with the diapause of their host. 相似文献
17.
Within-tree variation in fibre length and coarseness was studied in fifty trees of E. globulus and E. nitens to develop a non-destructive sampling strategy. Trees, aged 5 to 9 years, were sampled across a range of sites in southern
Australia. Simulated core samples were removed at six fixed heights easily accessible from the ground (0.5, 0.7, ... 1.5 m)
and at eight percentage heights (0, 10, 20, ... 70%). Whole-tree values, calculated from percentage height data, were correlated
with the core data to determine the optimal sampling height. Core samples were found to be reliable predictors of whole-tree
fibre length, but results were variable for fibre coarseness. Simulated cores taken from the recommended sampling heights
explained 87% and 71% of variation in whole-tree fibre length for E. globulus and E. nitens respectively and 54% and 45% of the variation in whole-tree fibre coarseness. Fibre length at all fixed heights showed good
correlations with whole-tree values at all sites for E. globulus. For E. nitens the correlations were slightly lower and variable across sites. Results for fibre coarseness varied across sampling heights
and sites for both species. The recommended sampling height for fibre length is 1.5 m for both species, whilst for fibre coarseness,
the recommended sampling heights are 0.9 and 1.1 m for E. globulus, and 0.9 and 1.3 m for E. nitens. Radial orientation of cores was not important and neither fibre length nor coarseness were related to tree size or basic
density. To estimate stand mean fibre length to an accuracy of ±5% would require sampling 9 whole trees or taking cores from
13 trees for E. globulus and 4 whole trees or cores from 8 trees for E. nitens. For estimating stand mean fibre coarseness, 10 whole trees of E. globulus and 7 whole trees are needed for E. nitens. Core sampling for stand mean coarseness would require more trees: 13 to 21 for E. globulus and 11 to 16 trees for E. nitens.
Received 17 September 1998 相似文献
18.
Forest decline has been attributed to the interaction of several stressors including biotic factors such as mistletoes and climate-induced drought stress. However, few data exist on how mistletoes are spatially arranged within trees and how this spatial pattern is related to changes in radial growth, responses to drought stress and carbon use. We used dendrochronology to quantify how mistletoe (Viscum album L.) infestation and drought stress affected long-term growth patterns in Pinus sylvestris L. at different heights. Basal area increment (BAI) trends and comparisons between trees of three different infestation degrees (without mistletoe, ID1; moderately infested trees, ID2; and severely infested trees, ID3) were performed using linear mixed-effects models. To identify the main climatic drivers of tree growth tree-ring widths were converted into indexed chronologies and related to climate data using correlation functions. We performed spatial analyses of the 3D distribution of mistletoe individuals and their ages within the crowns of three severely infested pines to describe their patterns. Lastly, we quantified carbohydrate and nitrogen concentrations in needles and sapwood of branches from severely infested trees and from trees without mistletoe. Mistletoe individuals formed strongly clustered groups of similar age within tree crowns and their age increased towards the crown apex. Mistletoe infestation negatively impacted growth but this effect was stronger near the tree apex than in the rest of sampled heights, causing an average loss of 64% in BAI (loss of BAI was ～51% at 1.3 m or near the tree base). We found that BAI of severely infested trees and moderately or non-infested trees diverged since 2001 and such divergence was magnified by drought. Infested trees had lower concentrations of soluble sugars in their needles than non-infested ones. We conclude that mistletoe infestation causes growth decline and increases the sensitivity of trees to drought stress. 相似文献
19.
The basal area and height growth of trees and saplings in silver fir–European beech single stem selection forest were studied
with regard to their social status and crown parameters of size, coverage, shading and vitality. On 24 permanent research
plots (20 m × 20 m each) all trees [diameter at breast height (dbh) ≥10 cm] and saplings (≥1.3 m tall and dbh <10 cm) were
surveyed. Repeated measurements of dbh (N = 1,608) and height (N = 1,135) 10 years apart enabled the calculation of annual basal area increment (BAI) of trees and saplings, and annual height
(HI) increment of saplings. To obtain the growth characteristics for individual trees and saplings, their social status and
crown parameters were assessed by rank. In the multivariate general linear model for BAI, social status, crown size and crown
coverage of individuals as the predictors, and dbh2 as the covariate, explained 70% of total variability. Similarly, social status, crown size, crown coverage and crown shading
had a significant impact on the HI of saplings, explaining 70% of total variability. Among the observed variables, social
status determined according to the individual’s position in vertical stand structure was, in addition to dbh, the most important
predictor for both BAI and HI. Significant differences were observed between the BAI and HI models for the main tree species
(European beech and silver fir), indicating their different growth characteristics. The applied method could be used as a
supplement to the more widely used approaches for studying basal area and height growth of individual trees in selection forest
stands. 相似文献
20.
C. A. Raymond L. R. Schimleck A. Muneri A. J. Michell 《Wood Science and Technology》2001,35(3):203-215
Within-tree variation in kraft pulp yield, predicted using near infrared reflectance analysis, was studied in thirty trees
of E. globulus and fifty trees of E. nitens to develop a non-destructive sampling strategy. Trees, aged 5 to 9 years, were sampled across a range of sites in southern
Australia. Simulated core samples were removed at six fixed heights easily accessible from the ground (0.5, 0.7, ... 1.5 m)
and at seven percentage heights (0, 20, 30, ... 70%). Whole-tree values, calculated from percentage height data, were correlated
with the core data to determine the optimal sampling height. Core samples were found to be good predictors of whole-tree pulp
yield for E. globulus, with simulated cores taken from the recommended sampling height (1.1 m) explaining more than 50% of variation in whole-tree
pulp yield. Results for E. nitens were variable with large site differences apparent. On high quality sites, core samples from the recommended sampling height
(0.9 m) were good predictors of whole-tree pulp yield, explaining around 60% of the variation. On poor quality sites, cores
were poor predictors of whole-tree pulp yield. Radial orientation of cores was not important and predicted pulp yield was
not related to tree size, basic density or fibre length. To estimate stand mean pulp yield to an accuracy of ±1% would require
sampling 6 trees of E. globulus and 4 trees for E. nitens using either multiple discs or core samples. A single sampling height (1.1 m) is recommended for sampling for basic density,
fibre length, fibre coarseness and predicted pulp yield in E. globulus. For E. nitens the recommended sampling height for basic density and fibre length is 0.7 m and 0.9 m is recommended for predicted pulp yield
on good quality sites.
Received 17 September 1998 相似文献