共查询到20条相似文献，搜索用时 22 毫秒
1.
Forest management is often carried out in different ways, without any appropriate environmental restrictions. Stands of pedunculate oak (Quercus robur L.) in Galicia (NW Spain) have been harvested by alternating high forest and, mainly, coppice forest. However, some totally inappropriate silvicultural treatments have been used, such as thinning of the best trees and inadequate pruning. The objective of the present study was to analyse how environmental characteristics affect the management of oak forests in Galicia. For this, a botanical inventory was carried out in 39 selected stands of Q. robur and a total of 42 parameters were measured, 4 of which were physiographical, 12 climatic, 19 edaphic and 7 silvicultural. In order to analyse the possible relationships among these variables, the silvicultural data were compared with the other data, by canonical correlation analysis. All parameters were correlated with the silvicultural regime, although the correlation was weak for the floristic data. It is therefore evident that the environmental conditions affect how forest stands should be managed, although this does not imply that more profitable use of the stands cannot be achieved than at present, and alternative silvicultural methods must be found to enable appropriate management and conservation of oak stands. 相似文献
2.
3.
While study by continental and American workers has continuedover a considerable period, little has been published in connexionwith forestry. A method is described using photoelectric cellphotometers and the results given of measurements made undercomparable stands of sessile and pedunculate oak (Quercus petraeaLiebe and Q. robur L.). These results confirm that sessile oakcasts more shade than pedunculate oak. 相似文献
4.
Acorns of sessile oak (Quercus petraea) will not tolerate prolongedsubmergence, but those of pedunculate oak (Quercus robur) survivevery well in regularly changed distilled water or tap-water.Survival is considerably worse in basic river water; the differencefrom tap-water is likely to be due either to the greater activityof organisms promoting decay, or to the prevalence of loweroxygen-tensions in river water. Storage in water under suitablycontrolled conditions might be a useful practical procedurewith pedunculate acorns. 相似文献
5.
The Wessex Silvicultural Group spent three years studying themanagement and silviculture of the oaks (Quercus robur L andQ petraea (Matt) Leibl) in the Wessex area. Low input methodsof establishment including the use of tree shelters and thetending and thinning of younger oak stands together with controlof timber quality were examined in twenty-one forests and estates.Environmental values were acknowledged. While Q robur has previouslypredominated, Q petraea is now generally preferred. 相似文献
6.
The paper describes the methods used in the field and in theoffice to determine the standing volumes and increments of 100-and 130-year old oak in the Forest of Bere, Hampshire, duringworking-plan revision. The figures obtained show that the standingvolumes and increments of sessile oak (Quercus petraea Liebe)are considerably higher than those of pedunculate oak {Q. roburL.) on the three sites investigated, namely, clays, sands, andgravels, while for both species sands appear to be the mostfavourable and gravels the least favourable soil types. Therewas little difference in the mean values for increment and standingvolume between the 100- and the 130-year old pedunculate oak. 相似文献
7.
José Miguel Olano Nere Amaia Laskurain Adrián Escudero Marcelino De La Cruz 《Annals of Forest Science》2009,66(1):105-105
8.
Jeroen Staelens Lieven Nachtergale An De Schrijver Margot Vanhellemont Karen Wuyts Kris Verheyen 《Annals of Forest Science》2011,68(1):89-98
Introduction
To increase our understanding of litterfall dynamics in mixed-species forests, seasonal and annual variations in litterfall mass and nutrient concentrations were assessed for a 60-year-old spontaneously developed forest dominated by silver birch (Betula pendula Roth), pedunculate oak (Quercus robur L.), and northern red oak (Quercus rubra L.) in Belgium. 相似文献9.
Episodes of dying back of pedunculate oak Quercus roburhaveoccurred in Europe. In this article, produced to mark the 70thvolume of Forestry, the 1920s episode, as described by contemporaryresearch workers, is evaluated. The second part of the paperis concerned with an accountof the 1989–1994 episode inGreat Britain and comparisons are made with occurrences elsewherein Europe. In Britain, one feature not previously recorded,was attack on declining trees by the buprestid beetle, Agriluspannonicus. 相似文献
10.
Marcos Barrio Anta Ulises Diéguez-Aranda Fernando Castedo-Dorado Juan Gabriel Álvarez González Klaus von Gadow 《Annals of Forest Science》2007,64(5):511-520
A model is required for accurate estimation of the merchantable volume of pedunculate oak (Quercus robur L.) trees in Galicia, northwestern Spain. Accordingly, the purpose of the present study was to obtain equations for predicting merchantable volumes and stem profiles of individual trees. For this reason, two compatible and four non-compatible volume systems were initially evaluated and fitted to data from 251 destructively sampled trees which were collected in stands located throughout the area of distribution of the species in Galicia. The outliers were removed to provide a data set of measurements from 3 090 sections, which was then available for fitting. A second-order continuous autoregressive error structure was used to account for autocorrelation. Comparison of the models was carried out using overall goodness-of-fit statistics and box plots of residuals against relative height or diameter class. The compatible volume system of Fang et al. [22] provided the best compromise in describing the stem profile and estimating merchantable height, merchantable volume and total volume and is therefore recommended for pedunculate oak stands in Galicia. 相似文献
11.
Four basic stages in the life of the oak wood (Quercus roburand Q. petraea) are defined and the factors which should influencethe manager's mind when he weighs density of stocking and lengthof bole against rotation to meet his particular requirementsare considered briefly in non-technical language. 相似文献
12.
Density management is the usual method used by silviculturiststo achieve a desired future stand condition, and one of themost effective methods of design, display and evaluation ofalternative density management regimes in even-aged stands isthe use of stand density management diagrams. In the presentstudy, we describe a method for developing thinning schedulesfor even-aged pedunculate oak (Quercus robur L.) stands in Galicia(north-western Spain), using a density management diagram. Thediagram integrates the relationships among stand density, dominantheight, quadratic mean diameter and stand volume in a singlegraph. The data used in its construction were obtained from172 sample plots located throughout Galicia. The diagram isbasically composed of two equations: the first relates the quadraticmean diameter to the stand density and dominant height; thesecond relates the stand volume to the quadratic mean diameter,stand density and dominant height. These equations were fittedsimultaneously using full information maximum likelihood. Therelative spacing index is used to characterize the growing stockand the diagram provides isolines for dominant height, numberof trees per hectare, quadratic mean diameter and stand volume.Dominant height isolines together with the site index curvesallow specification of the timing of thinnings while intermediateand final harvest volumes are calculated using the stand volumesisolines. 相似文献
13.
Pressler cores were taken of Quercus petraea and Q. robur treesfrom young German provenance stands and mature mixed plantationsin England. The concentration of total phenolics extracted fromthe outer heartwood was measured and significant differencesfound between the two species. Concentrations of oak lactones,measured from provenance samples, also varied significantlybetween the species. However, the difference in total phenolicsbetween species was much lower among the trees from the mixedplantations than from the provenance trials. Q. petraea wascharacterized by lower levels of total phenolics but greaterconcentrations of oak lactones than Q. robur. A comparison betweenlate and early flushing Q. petraea trees found no significantdifference in total phenolics between these phenological types. 相似文献
14.
• Background and purpose
A complex interplay between biotic and abiotic factors is believed to be responsible for several oak declines in pedunculate oak (Quercus robur L.). This study aims to clarify the temporal process of oak declines, as well as identifying individual tree and environmental variables that affects growth rate and that may increase the risk of mortality. The study was performed in southern Sweden at three sites. 相似文献15.
We used morphological analysis to assess species composition of natural regenerations and progeny plantations established from two mixed oak stands in Jamy and Legnica, Poland. Despite equal proportions of pedunculate (Quercus robur) and sessile oak (Quercus petrea) in seed stands, the species composition differed strikingly. In all progeny populations, pedunculate oak dominated, reaching 89.5% and 96.6% in Legnica and Jamy, respectively. However, sessile oak predominated in natural regenerations. Morphological studies indicated a varied number of phenotypically intermediate or mosaic individuals. Among artificial populations, the highest number of putative hybrids was observed in Legnica (average 2.5%) and the lowest in Jamy (average 0.2%). Hybrids in natural regeneration were 1% in Legnica and 8% in Jamy. The disproportionate species composition could result from either unintentional indirect acorn selection during collection or selection in nursery practice. We discuss the role of ecophysiological differences between species in biased species representation in progeny populations. 相似文献
16.
Acorns collected from a range of Quercus robur L. and Q. petraea(Matt.) Liebl. populations were germinated and grown in an unheatedgreenhouse using a standard commercial compost. Total seedlingdry weight did not increase until the end of the growing season,with Q. robur and Q. petraea seedlings showing mean dry weightincreases of 211 per cent and 414 per cent respectively. Oakseedlings appear to depend upon cotyledon reserves of carbohydrate,P, K and Mg during most of the first year of growth, but relyon external sources of Ca. Seedlings become independent of thecotyledons at the end of the first growing season. 相似文献
17.
A noticeable decline and physiological weakening of pedunculate oak (Quercus robur L.) has been recorded in the past decade in lowland parts of Slovenia. The triggers were dry climate, unfavourable precipitation patterns and human influence that brought about changes in watercourses and water tables. Regeneration and future management of this tree species is therefore questionable. To define a critical groundwater table which would permit successful regeneration, planted and naturally grown seedlings were compared in two forests differing in the degree of decline and physiological weakness of adult pedunculate oak trees. Comparison of stomatal conductance and pre-dawn water potential (PWP) showed differences of seedlings between and within forest complexes. Stomatal conductance dropped below 100 mmol m−2 s−1 at PWP values below −1.0 MPa, while closure of stomata was caused by a PWP between −1.6 and −1.9 MPa. Increased water stress equalized photosynthetic yield in both natural and planted oaks below −1.4 MPa. 相似文献
18.
Free growth is a type of heavy thinning which aims to maximizediameter increment and produce valuable timber on a relativelyshort rotation. An experiment is described which investigatedthe application of free growth to a stand of oak {Quercus petraeaand Q. robur) planted in 1930. At age 58 free growth thinninghad resulted in a mean diameter at breast height of 39.0 cmwith an estimated mean tree volume of 0.98 m3, compared with29.3 cm and 0.52 m3 for equivalent crown thinned trees. Discountedcash flow calculations showed that free growth thinning of oakcould be justified using a 3 per cent discount rate assumingthat the increased intensity of pruning results in a large proportionof veneer quality timber; an independent assessment indicatedthis may be possible. Free growth thinning of oak is not a commonpractice in British broadleaved silviculture probably becauseof the cost of controlling epicormic shoots. It is suggestedthat it may be more appropriate to other species such as ash,sycamore and wild cherry. 相似文献
19.
Kris Vandekerkhove Luc De Keersmaeker Norbert Menke Peter Meyer Pieter Verschelde 《Forest Ecology and Management》2009
The accumulation of dead wood and its characteristics are analysed in forests that have been withdrawn from regular silvicultural management and left unmanaged between 10 and 150 years ago. These forests are dominated by beech (Fagus sylvatica) and oak (Quercus robur and Quercus petraea) and located in the lowlands of North-western and Central Europe. 相似文献
20.