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21.
Claude Plassard Julien Louche Muhammad A. Ali Myriam Duchemin Elvira Legname Benoît Cloutier-Hurteau 《Annals of Forest Science》2011,68(1):33-43
• Introduction
Phosphorus (P) is often the first or second element limiting aboveground net primary productivity of forests. Besides low available inorganic orthophosphate (Pi) concentrations, soil may contain high total P contents, as insoluble mineral P or as organic P. Most plants form mycorrhizal associations that improve their P nutrition. Three main hypotheses have been proposed to explain this positive effect through an increase of (1) P mobilisation from mineral P, (2) P mobilisation from organic P and (3) soil exploration and P uptake. However, the positive effect of mycorrhizal symbiosis may be variable with the fungal species forming the association. This could be due to the different abilities of mycorrhizal fungi to mobilise P and/or to take up Pi from the soil. 相似文献22.
Ghislain Vieilledent Benoît Courbaud Georges Kunstler Jean-François Dhôte 《Annals of Forest Science》2010,67(3):305-305
Question
Tree mortality can be modeled using two complementary covariates, tree size and tree growth. Tree growth is an integrative measure of tree vitality while tree diameter is a good index of sensitivity to disturbances and can be considered as a proxy for tree age which may indicate senescence. Few mortality models integrate both covariates because classical model calibration requires large permanent plot data-sets which are rare. How then can we calibrate a multivariate mortality model including size and growth when permanent plots data are not available?Location
To answer this question, we studied Abies alba and Picea abies mortality in the French Swiss and Italian Alps.Method
Our study proposes an alternative semi-parametric method which includes a random sample of living and dead trees with diameter and growth measurements.Results
We were able to calibrate a mortality model combining both size-dependent and growth-dependent mortality. We demonstrated that A. alba had a lower annual mortality rate (10%) than P. abies (18%) for low growth (< 0.2 mmyear?1). We also demonstrated that for higher diameters (DBH ≥ 70 cm), P. abies had a higher mortality rate (0.45%) than A. alba (0.32%).Conclusion
Our results are consistent with the mechanisms of colonization-competition trade-off and of successional niche theory which may explain the coexistence of these two species in the Alps. The method we developed should be useful for forecasting tree mortality and can improve the efficiency of forest dynamics models. 相似文献23.
Simon Bilodeau-Gauthier Daniel Houle Christian GagnonBenoît Côté Christian Messier 《Forest Ecology and Management》2011,261(1):95-104
Partitioning of elements in tree xylem is being increasingly studied, as it suggests that elements are potentially mobile within the xylem long after their uptake. A recent study revealed that only the most mobile xylem fraction (water-soluble) of base cations (calcium [Ca], magnesium [Mg], and potassium [K]) increased at higher soil acidity, while the two mobile fractions (water- and acid-soluble) of acidic metals—potentially phytotoxic aluminium (Al), cadmium (Cd) and manganese (Mn)—were significantly enhanced on very acid soils. The current paper presents an investigation of soil-wood chemistry relationships with basal area tree growth. It was hypothesized that the growth of sugar maple would be reduced by low base cation and high acidic metal concentrations in the xylem mobile fractions. Sugar maple trees (n = 55) from six watersheds in southern Quebec, Canada were analysed by sequential chemical extractions for the water-soluble, acid-soluble and residual fractions of base cations (Ca, K, Mg) and acidic metals (Al, Cd, Mn) in xylem. Generally, tree growth was positively correlated to concentrations of base cations in wood (ρ = 0.27-0.50) and soil (ρ = 0.41-0.67), and negatively correlated to concentrations of acidic metals in wood (ρ = −0.33 to −0.52) and soil (ρ = −0.67). However, these relations differed depending on the element fraction considered. Water- and acid-soluble xylem concentrations of base cations and Al were among the best predictors of growth trends (R2 = 0.46-0.51). The relationship between acidic metals and tree growth is further discussed. 相似文献
24.
New Forests - Between the nineteenth and early twentieth centuries, large-scale afforestation projects were undertaken in the Swiss Prealps. The Swiss stone pine (Pinus cembra L.), an emblematic... 相似文献
25.
Blaise Ratcliffe Foster J. Hart Jaroslav Klápště Barry Jaquish Shawn D. Mansfield Yousry A. El-Kassaby 《Annals of Forest Science》2014,71(3):415-424
Context
Wood quality traits are important to balance the negative decline of wood quality associated with selection for growth attributes in gymnosperm breeding programs. Obtaining wood quality estimates quickly is crucial for successful incorporation in breeding programs.Aims
The aims of this paper are to: (1) Estimate genetic and phenotypic correlations between growth and wood quality attributes, (2) Estimate heritability of the studied traits, and (3) Assess the accuracy of in situ non-destructive tools as a representative of actual wood density.Methods
Wood density (X-ray densitometry), tree height, diameter, volume, resistance drilling, acoustic velocity, and dynamic modulus of elasticity were estimated, along with their genetic parameters, for 1,200, 20-year-old trees from 25 open-pollinated families.Results
Individual tree level heritabilities for non-destructive evaluation attributes were moderate ( $ {\widehat{h}}_i^2=0.37-0.42 $ ), wood density and growth traits were lower ( $ {\widehat{h}}_i^2=0.23-0.35 $ ). Favorable genetic and phenotypic correlations between growth traits, wood density, and non-destructive evaluation traits were observed. A perfect genetic correlation was found between resistance drilling and wood density (r G ?=?1.00?±?0.07), while acoustic velocity and dynamic modulus of elasticity showed weaker genetic correlations with wood density (r G ?=?0.25?±?0.24;?0.46?±?0.21, respectively).Conclusion
This study confirmed that resistance drilling is a reliable predictor of wood density in western larch, while the weak genetic correlations displayed by acoustic velocity and dynamic modulus of elasticity suggest limited dependability for their use as fast in situ wood density assessment methods in this species. 相似文献26.
We compared the acidity, the external acid neutralizing capacity and the buffering capacity of leaves of four commercially important tree species, largetooth aspen (Populus grandidentata Michx.), sugar maple (Acer saccharum Marsh.), paper birch (Betula papyrifera Marsh.) and balsam fir (Abies balsamea (L.) Mill), at two sites of contrasting soil fertility in southern Quebec. External acid neutralizing capacity (ENC) of leaves was determined by measuring the change in pH induced by soaking fresh leaves in an acidic solution (pH 4.0) for two hours. The ENC was highest for largetooth aspen (14.3 micro equiv H(+) g(-1)), and lowest for sugar maple and balsam fir (< 5 micro equiv H(+) g(-1)). The buffering capacity index (BCI) was determined by measuring the amount of acid necessary to produce a change of 5 micro equiv H(+) in the leaf homogenate. The BCI ranged from 883 micro equiv H(+) g(-1) for largetooth aspen to less than 105 micro equiv H(+) g(-1) for sugar maple and balsam fir. Leaves of sugar maple and balsam fir had a lower internal pH and a higher percentage of ENC over BCI than paper birch and largetooth aspen. Overall, ENC was correlated with the concentration of all leaf nutrients except Ca, and BCI was correlated with Mg, N and Ca. The site effect was relatively unimportant for all variables. 相似文献
27.
Anne Poszwa Bruno Ferry Benoît Pollie Catherine Grimaldi Pierre Charles-Dominique Michel Loubet Etienne Dambrine 《Annals of Forest Science》2009,66(5):512-512
28.
29.
Gyula Pinke Péter Karácsony Zoltán Botta-Dukát Bálint Czúcz 《Journal of pest science》2013,86(3):621-631
The weed control of sunflower is a great challenge for farmers throughout the World. In Hungary, one of the greatest concerns is the pernicious weed Ambrosia artemisiifolia, which produces allergenic pollen. The main goal of this study was to identify cultural, weed-management and environmental factors determining weed species composition and the abundance of A. artemisiifolia in sunflower fields. Altogether 49 sunflower fields across Hungary were surveyed for their weed flora, and 30 environmental, cultural and weed-management factors were measured. Using a minimal adequate model containing 14 terms, 38 % of the total variation in species data could be explained. Soil Mg and Ca content, preceding crop, temperature, and field size had significant effects on species composition. Most of the herbicides were effective against annual grass species, but no herbicide was universally effective against broad-leaved weeds. Almost all types of weeds were efficiently reduced with mechanical weed control. A relatively high share of the explanatory variables were environmental factors, suggesting that the success of weed management in sunflower fields strongly depends on a complex of edaphic and climatic constraints. The abundance of Ambrosia artemisiifolia was positively correlated with high soil Ca content, lower temperature, the preceding crop being a cereal, and smaller field sizes; while considering herbicides it seemed to be most sensitive to fluorchloridon and propisochlor application. To reduce noxious broad-leaved weed species could require specific herbicide mixtures, and mechanical weed control should also be integrated into weed management. 相似文献
30.
Synchrony between development of five corn hybrid varieties of various seasonal growing rates (FAO numbers), seasonal flight
pattern of male cotton bollworm, Helicoverpa armigera Hb. (Lepidoptera: Noctuidae), as monitored by pheromone traps, and the subsequent appearance of newly hatched larvae on developing
cobs were studied at Mezőhegyes, South-Hungary, in 2003 and 2004. The phenological stages of corn hybrids were evaluated using
the Iowa State University Scale (R1–R5), the flight of male moths was monitored by large capacity, funnel type of pheromone traps and the appearance of freshly
hatched larvae on developing cobs were counted by visual inspection. The synchrony between the flight peak of male moths and
the peak apperance of L1 larvae on cobs was investigated by cross-correlation. In 2003 (average daily temperatures 20.7°C, average daily relative
humidity 59.9% for the period of 4–18 July) “DK 391”, “DK 443” and “Maraton” hybrid varieties already reached silking stage
(R1) by the time when pheromone traps indicated a peak, at 7 July (peak capture at 3-day intervals 755.5 males/traps). The number
of L1 larvae peaked on developing cobs of these varieties also at 7 July (7.0, 4.0 and 3.8 larvae/50 cobs, respectively). The synchrony
between the flight peak of male moths and the peak appearance of L1 larvae on cobs was proven (LAG = 0). A rather similar trend was observed in “Vilma” hybrid variety: it reached R1 stage at 7 July, and L1 larvae appeared only a few days later (11 July, 3.8 larvae/50 cobs) (LAG = −1). However, “Maxima” hybrid variety reached
R1 stage 1 week later (14 July) than the time of peak captures. Here L1 larvae peaked as late as at 18 July (0.8 larvae/50 cobs), i.e., only after the cob had reached R1 stage (LAG = −3). A reverse order of dates of R1 stage and peak capture was observed in “Maxima” in 2004 (average daily temperatures; 22.5°C, average daily relative humidities
72.6% for the period of 15 July–6 August): it reached R1 stage at 19 July, while peak trap captures were recorded at 6 August (peak capture at 3-day intervals 20.5 males/traps).
L1 larvae were found in the highest numbers on 2 August (1.5 larvae/50 cobs), practically in synchrony with peak caputres (LAG = 0).
“Káma” reached R1 stage in 16 July, and L1 larvae peaked at 2 August (1.3 larvae/50 cobs) (LAG = 0). On the rest of the corn varieties larvae were found only in too
numbers for performing statistical analysis. We conclude that in order to predict the appearance of L1 larvae, the phenological stage of the corn variety and the seasonal flight pattern of moths, as measured by large capacity
pheromone traps, should be considered in combination. If the corn variety already reached R1 stage, L1 larvae appear on cobs as early as the time of peak flight of moths. However, no young larvae appear on cobs despite of high
trap captures, until the corn reaches the R1 stage. These findings are discussed in the view of specifying optimal timing of a pesticide application. 相似文献