共查询到20条相似文献，搜索用时 78 毫秒
1.
The physiological status of ash (Fraxinus excelsior L.), sessile oak (Quercus petraea (Matt.)) and sycamore (Acer pseudoplatanus L.) seedlings sampled from nurseries in Ireland between October and May, 1995/1996 and 1996/1997 was investigated. The results of heat treatments applied to taproots in vitro and evaluated using root electrolyte leakage (REL) indicated that sycamore was more easily damaged than the other species but lift date effects were small in all species. Dormancy release began later each year in ash (mid-November) than in oak or sycamore (late October to early November). The results of the REL and other data indicated that there was little change in stress resistance from November to about March (and April for some parameters). Sycamore was most active (highest shoot xylem pressure potential, REL, and root growth potential) during the winter, suggesting that adverse handling during this period is likely to reduce plant quality than in ash or oak. Field performance was good regardless of lifting/planting date. 相似文献
2.
Silvopastoral systems in Europe offer the potential of introducing environmental benefits while at the same time increasing the diversity of farm outputs. The establishment of new silvopastoral systems by planting young trees into existing pasture was investigated at a site in North Wales, UK. Two tree species, sycamore (Acer pseudo-platanus L.) and red alder(Alnus rubra Bong.), were planted into pasture at a range of densities and planting arrangements. Growth of trees planted in farm woodland blocks (2500 stems ha–1) was compared with the growth of trees planted at 400 stems ha–1 in clumps and dispersed throughout the plot and at 100 stems ha–1 (dispersed). Over the first six years after planting, alder trees were significantly taller and larger in diameter than sycamore. Sycamore trees planted at close spacing in farm woodland or clumped arrangements were significantly larger in diameter than widely spaced sycamore at 100 and 400 stems ha–1. Livestock productivity was unaffected by the presence of trees during the six-year establishment phase of the system. The planting of trees in a clumped pattern appears to combine silvicultural benefits to tree growth with agricultural benefits of maintaining livestock production while trees are established.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
3.
The effect of nitrogen supply on root growth and development in sycamore and Sitka spruce trees 总被引：3，自引：0，他引：3
Sycamore (Acer pseudoplatanus L.) and Sitka spruce (Picea sitchensis(Bong.) Carr.) were grown in sand culture in glasshouses withtwo levels of N supplied with irrigation 1.0 (deficient) and6.0 (sufficient) molNm–3, all as NH4NO3. Providing trees with a sufficient N supply increased both theirabove ground growth and N content compared with the N deficientplants. Provision of the generous N supply also altered thedistribution of growth between leaves and roots, with the N-deficientplants having a higher root:leaf or root:needle ratio than thewell fertilized trees. Provision of a generous N supply stimulatedroot growth, especially at the later harvests, which was reflectedmainly in growth of the tap root in sycamore. There was an increasein both root mass and root diameter with N supply. When thegrowth of white roots was monitored using a borescope, it wasshown that there were significantly more new roots producedby the well-fertilized trees. The borescope data also showeddetail of the bimodal seasonal pattern of root growth underhigh N in Sitka spruce which related to trends in nitrogen uptake. 相似文献
4.
G. Weber-Blaschke R. Heitz M. Blaschke C. Ammer 《European Journal of Forest Research》2008,127(6):465-479
This study aimed to improve knowledge about the nutritional status, site requirements and site classification for European
ash (Fraxinus excelsior L.) and sycamore maple (Acer pseudoplatanus L.) by reinvestigating young plantations from 1991/1992 on windfall-affected areas in Bavaria/Germany after another decade.
Compared to the first survey in 1995, most stands improved their nutritional status until 2006. With the data set of element
concentrations in leaves of ash and sycamore available, the range of adequate nutrition could be determined for these species
in the pole stage phase. Both species show considerable height growth on a wide range of sites. Mean annual height growth
of dominant sycamore trees increased with rising foliar N or P concentrations but not for Ca, Mg, K, Mn, Fe and Al. For ash,
there was no relationship between the foliar nutrient level of any element and mean annual height growth. However, total height
around age 20 was favourably influenced by high base saturation and a good water supply at well-drained sites. On acid soils,
where nutrients are delivered by subsurface water flow, well-growing stands are found as well. Soil water status according
to the state forest soil classification had no significant impact on mean annual height growth. Ash and sycamore show reduced
productivity on some (moderately) dry soils and fail on poorly drained moist sites. Based on these results, the classification
of forest sites suitable for ash and sycamore within the Bavarian study sites was revised.
Dedicated to Professor Dr. Karl-Eugen Rehfuess on his 75th birthday. 相似文献
5.
Growth and mortality in underplanted tree seedlings in response to variations in canopy closure of Norway spruce stands 总被引：2，自引：0，他引：2
Lof Magnus; Karlsson Matts; Sonesson Kerstin; Welander Torkel N.; Collet Catherine 《Forestry》2007,80(4):371-383
Six broadleaved tree species and Picea abies (L.) Karst. wereplanted under spruce plantations of varying densities, in Sweden.Treatments included control (994 stems ha–1), dense (538stems ha–1), sparse (294 stems ha–1) and gap (0stems ha–1) overstory treatments. There was an increasein height and diameter growth from control to sparse overstorytreatment of all underplanted tree species except for ash (Fraxinusexcelsior L.) and Norway maple (Acer platanoides L.). Site conditionsmay have hampered the growth of these species, as well as wildcherry (Prunus avium L.). Both oak (Quercus robur L.) and sprucehad greater growth in the gap treatment, relative to the othertreatments. Insecticide application did not influence seedlinggrowth or survival. The performance of beech (Fagus sylvaticaL.), lime (Tilia cordata Mill.), spruce and oak was consistentwith shade tolerance ranking. Beech and lime had a very highsurvival rate, even under the densest canopy. The growth andmortality of ash, maple and wild cherry differed significantlyfrom what was expected. This experiment demonstrated significantvariation in interspecific growth and mortality between sevenplanted tree species in relation to canopy density. Correctsite and species selection is crucial when underplanting inshelterwood systems. 相似文献
6.
Katja Albert Peter Annighöfer Jens Schumacher Christian Ammer 《Scandinavian Journal of Forest Research》2014,29(3):210-221
With an increasing demand of sustainable raw materials for bioenergy use, coppicing as management approach to increase the biomass production of forests is becoming of greater importance. This study describes the parameterization of biomass equations for six tree species traditionally used in coppices forests, namely sycamore maple (Acer pseudoplatanus L.), field maple (Acer campestre L.), European ash (Fraxinus excelsior L.), European hornbeam (Carpinus betulus L.), downy birch (Betula pubescens Ehrh.), and common hazel (Corylus avellana L.) growing in coppice-with-standard systems in Lower Saxony, Germany. The parameterization was based on measurements of over 950 trees sampled from two forest sites. The sampled trees were felled and separated into three biomass compartments (stem, coarse branches, and fine brushwood) and weighed on site. The dry weight of sub samples from each compartment was measured. Equations were derived for total aboveground biomass, stem biomass, and crown biomass using regression analyses. We either used diameter at breast height as single independent explanatory variable or in combination with tree height. Biomass production of stump sprouts and generatively grown stems was compared for ash and sycamore maple. In the same age classes, it was found that ash stump sprouts had a slightly higher production than seed-grown stems. For sycamore maple, no difference was detected. 相似文献
7.
| – |
• Construction cost (g glucose g−1), chemical composition and morphology of leaves of beech (Fagus sylvatica L.) and two co-occurring valuable broadleaved species (sycamore maple — Acer pseudoplatanus L. — and ash — Fraxinus excelsior L.) were investigated along a horizontal light gradient (3–60% of above canopy radiation) and from top to bottom within the
crowns in a fairly even-aged mixed-species thicket established by natural regeneration beneath a patchy shelterwood canopy. 相似文献
8.
Conversion of monoculture plantations to mixed stands with greater diversity is an important aim of sustainable forest management, and in Britain, this is concentrated on the restoration of native broadleaved woodland on ancient woodland sites that were planted with conifers. Current British guidelines for this restoration have rarely been examined, and this study is the first to test their value for natural regeneration. The survival and growth of naturally regenerating ash (Fraxinus excelsior L.) seedlings was observed in thinned, selectively felled and clearfelled plots within a c. 40-year-old stand of Corsican pine (Pinus nigra Arnold ssp. laricio Maire). After felling in 2001, the ground flora in all treatments became dominated by bramble (Rubus fruticosus L. agg.) and its cover 5 years after felling was 75–95?% at a height of 0.9–1.2?m. During the study, seedling numbers declined 80–90?%. Although bramble had some adverse effects, seedling survival was unaffected by felling treatment. Seedling growth varied between treatments with those in the clearfell being tallest. Mean height of seedlings was always less than that of bramble, but by 2006 65?% of quadrats in the clearfelled plots had well-established individuals taller than the bramble compared with 35?% in the thinned plots. Models that described the relationships between seedling growth, basal area and bramble were complex, but results clearly indicate that maintaining canopy cover during restoration is probably an ineffective method of suppressing bramble on sites where it grows well. Results do not support the current British advice on conversion, but this may reflect the characteristics of pine canopies and the maintenance of canopy cover during conversion may be appropriate in stands of species, which cast more shade. 相似文献
9.
10.
The results of an experiment to investigate the early growthand form of ten different provenances of Norway maple (Acerplatanoides L.) are described. Two sites were planted and after8 years survival was 88 per cent and 95 per cent and heightincrement was 402 cm and 201 cm; confirmmg the potential ofNorway maple to be a productive forest tree. Provenances thatperformed well were from Germany, the Netherlands, Denmark andYugoslavia; exact locations were not known for all seed collections.A provenance from Russia was included, material from this fareast has rarely been tested in Britain. However, as expected,its performance was relatively poor. The main constraint tofurther planting of Norway maple is the palatability of thebark to grey squirrels (Sciurus carolinensis Gmelin.). However,it is a useful tree for high pH and heavy soils and as an alternativespecies to sycamore (Acer pseudoplatanus L.). 相似文献
11.
Beech woodland can be restored by direct planting of beech (Fagussylvatica L.) seedlings in abandoned areas, but this methodis generally avoided in forestry because of the growth difficultiesof beech in full-light conditions. This study tested a methodthat consists of planting beech seedlings in full-light conditionswith silver birch (Betula pendula Roth.) or Scots pine (Pinussylvestris L.) as nurse trees. A total of 65 two-year-old beechseedlings surrounded by either 3, 4, 5 or 6 pine or birch seedlingsor without competitors were planted in bare-soil open-fieldconditions in Central France. Tree growth and light availabilitywere monitored at the end of each of the following 3 years,and soil moisture was also measured the last year. At the endof the experiment, aerial biomass measurements were made onthe beeches. Results showed that relative beech growth in termsof diameter was significantly reduced by the local neighbouringtrees and that this reduction was particularly noticeable inthe pine treatments where there was extensive pine seedlingdevelopment. In contrast, relative beech height did not exhibitany significant variations among the treatments. Light availabilitywas decreased by the neighbouring trees, especially in the pinetreatments. Light reduction was more pronounced in the last2 years and in the middle or lower parts of the canopy of thesubject beech. Soil water content was lower under the pine canopiesthan under the birch canopies, and was positively correlatedto beech relative diameter growth. Specific leaf area, height-to-diameterratio and crown length-to-crown width ratio weakly but significantlyincreased with competition from the neighbours. Beech biomasspartitioning was only weakly affected by the treatments. Thisstudy showed that nurse trees tend to reduce beech growth butimprove form although effects remained weak due to the insufficientlength of the experiment. Further studies are also needed toquantify the effects of the neighbourhood on the growth of competitiveherbaceous vegetation and on changes in the microclimatic conditions. 相似文献
12.
We examined the short-term effects of group-selection harvestingwith seed tree retention on the diversity, abundance and establishmentof tree seedlings in a northern hardwood forest in the UpperPeninsula of Michigan (49 openings, 20 closed canopy referencesites). Three opening sizes were examined – opening radius0.5 x canopy height (267 ± 62 m2, n = 16), 0.75 x canopyheight (642 ± 85 m2, n = 17) and 1.0 x canopy height(1192 ± 155 m2, n = 16) (canopy height = 22 m). A singleyellow birch (Betula alleghaniensis Britt.) seed tree was retainedin the centre of each opening. Tree seedling density was significantlyhigher in the largest group-selection opening than at the closedcanopy reference sites (P < 0.05), the main factor for thiswas the increased proportion of yellow birch, red maple (Acerrubrum L.) and other minor species. Nevertheless, yellow birchwas still a minor component of the developing gap cohort, comprising5.9 per cent of the seedlings and 1.1 per cent of the saplings.Within openings, microsite variables, such as per cent coversof bare soil and coarse woody debris, were the best predictorsof yellow birch occurrence and density. Our results suggestthat microsite limitations and competing vegetation may greatlyreduce the efficacy of openings for ensuring the maintenanceof mid-tolerants. 相似文献
13.
In direct-seeded woodlands and nursery seed-beds, weeds canrapidly invade newly sown areas, leading to death or suppressionof tree seedlings. Hand weeding is usually expensive, and thesafe use of broad-spectrum contact herbicides is seldom possible.Hence in the work reported here, the tolerance of young treeseedlings to the potentially more selective, post-emergenceherbicides clopyralid, cycloxydim and metazachlor, was tested.Seedlings of Fraxinus excelsior L. (ash) with two to four expandedtrue leaves (2–4 ETL), Fagus sylvatica L. (beech) (2–4ETL), Acer pseudoplatanus L. (sycamore) (4–6 ETL), Prunusavium L. (cherry) (6–8 ETL) and Quercus robur L. (oak)(6–8 ETL) appeared to tolerate applications of cycloxydimat a rate of 0.45 kg a.i. ha–1. Applications of 0.2 kga.i. ha–1 clopyralid or 1.25 kg a.i. ha–1 metazachloralso appeared to be generally tolerated, but did cause somesuppression of annual growth increment in Q. robur, P. avium,F. sylvatica and A. pseudoplatanus, particularly where repeatapplications were made to the earliest growth stages. Seedlingsurvival was unaffected by any herbicide treatment. Mixturesof all three herbicides were no more damaging than the sameherbicides applied separately. Therefore, depending on treespecies and growth stage, it appears that clopyralid could potentiallybe safely used to control a range of herbaceous weed species,metazachlor a variety of seedling or germinating weeds and cycloxydima range of established grass weed species, in direct sown woodlandsor nursery seed-beds, although further research is advisableto confirm crop safety. 相似文献
14.
Aleš Kadunc 《European Journal of Forest Research》2007,126(3):349-358
Sycamore (Acer pseudoplatanus L.) is a tree species with highly valuable wood. Similar to European beech (Fagus sylvatica L.), the stemwood of sycamore can be devalued due to the discolouration i.e. brown heart (hearwood discolouration, hereafter).
This paper aims to establish the influence of tree traits and site characteristics on the formation of heartwood discolouration
and the possibility of predicting the occurrence of heartwood discolouration. For this purpose, 351 sycamore trees from 38
sites in Slovenia, most of them on carbonate bedrock and in the mountain vegetation belt, were analysed. Stem analysis was
carried out on all the trees and the age, diameter at breast height (dbh), height of crown base, forking and crown size, were
established. On the stump and upper fronts of the first and second logs, the maximum heartwood discolouration diameter was
measured. Using logistic regression, the positive influence of age, relative crown length and average diameter increment on
the formation of heartwood discolouration was ascertained. Conversely, the probability of heartwood discolouration was diminished
by diameter increment in the last 20 years. In the less productive sites, the probability of formation of heartwood discolouration
was relatively high in small diameter trees, but it increased slowly with diameter. Tree forking also contributed to a large
extent of the heartwood discolouration. After the diameter at breast height achieves 45 cm, the formation of heartwood discolouration
on the first log is highly probable. As in beech, the heartwood discolouration increases along the stem axis up to a height
of 6–8 m, and decreases in the higher parts of the tree. 相似文献
15.
R. L. Jinks 《New Forests》1995,10(2):183-195
The effect of propagation environment on the rooting of field collected leafy cuttings of ash (Fraxinus excelsior, sycamore (Acer pseudoplatanus) and sweet chestnut (Castanea sativa) was investigated in two experiments. In the first experiment, rooting of all three species in mist enclosed inside a polythene tent was greater than 50%, while rooting of ash cuttings was reduced from 63% in enclosed mist to only 16% in open mist. Rooting in open mist, enclosed mist, and contact polythene was studied in a second experiment. Sycamore cuttings rooted equally well in the two mist systems with an average rooting of 78%. In contrast cuttings of both ash and sweet chestnut rooted most under the enclosed mist system, at 64 and 46% respectively. Rooting of ash cuttings was again depressed in the open mist system where less than 30% of cuttings rooted. This reduction was related to an increase in the percentage of cuttings which remained alive without rooting, while showing proliferation of callus at the cutting base. The percentage of sweet chestnut cuttings which callused without rooting was also much greater in the open mist system than in enclosed mist or contact polythene. 相似文献
16.
The early growth of British and continental provenances of sycamore,Acer pseudoplatanus L., was compared in the nursery and in fieldtrials at five farm-forestry sites. There were significant differencesbetween provenances in height and root-collar diameter in thenursery. After four seasons in the field the ranking of provenancesfor height had changed considerably and differences betweenprovenances were no longer significant summing over sites. Ofthe four continental provenances, two, from Denmark and Germany,performed better than the British provenances at those siteswhere they were included. Results are discussed in relationto the selection of improved sycamore planting material forthe forest industry. 相似文献
17.
Data are presented from unreplicated Scots pine {Pinus sylvestrisL.) sample plots in Thetford Forest which have been differentiallyattacked by Fomes annosus (Fr.) Cooke. Volume production ofseverely infested crops differs markedly from that forecastby management tables. The volume of dead trees may not representthe total loss of volume in these plots as there appears alsoto be a reduction in the growth of the remaining live trees.These observations may have considerable significance in forecastingfuture volume production from stands attacked by F. annosusand also in deciding the optimum time for their replacement. 相似文献
18.
Short rotation woody biofuel plantations on reclaimed surface mines in Appalachia can diversify domestic energy supplies and facilitate the reforestation of these disturbed lands. This study examined growth, survival, biomass accumulation and allocation, and nitrogen concentrations following two growing seasons in American sycamore (Platanus occidentalis L.) and black locust (Robinia pseudoacacia L.) seedlings receiving irrigation, granular fertilization, and irrigation + fertilization compared with untreated controls. Fertilization increased basal diameter, height, and stem mass of American sycamore following two growing seasons. Increased stem production was attributed to accelerated development and not shifts in biomass allocation due to treatment. Irrigation and irrigation + fertilization treatments did not enhance growth or biomass accumulation of American sycamore. Similarly, black locust basal diameter, height, and stem mass did not differ among the treatments. Browse surveys showed that more than 76% of black locust seedlings experienced arrested or retrogressed growth due to browse; less than 3% of American sycamores were browsed. This intensive browse by ungulates, likely including reintroduced elk, may have affected growth differences among species and confounded the effects of treatments on black locust. Survival was unaffected by treatment in both species, but mean survival was greatest in American sycamore (80%) compared to black locust (58%). Per tree total nitrogen uptake was highest in fertilized American sycamore (7.9 g) and lowest in irrigated American sycamore (0.9 g). The results of our study suggest that granular fertilizer applications can accelerate seedling growth on reclaimed surface mines in the Appalachian region. 相似文献
19.
Analysis of the pore-size distribution and fiber saturation point of native and thermally modified wood using differential scanning calorimetry 总被引：1，自引：0，他引：1
Mario Zauer Jens Kretzschmar Livia Großmann Alexander Pfriem André Wagenführ 《Wood Science and Technology》2014,48(1):177-193
The aim of this paper was to investigate pore-size distributions in the nano-diameter range of wood and their alteration due to thermal modification of wood using thermoporosimetry, and to find out what consequences can be derived regarding the biological durability. Thermoporosimetry is a technique that is based on the measurement using differential scanning calorimetry (DSC). The method is based on the fact that frozen water contained within small pores is at elevated pressure and therefore has a depressed melting temperature as a function of the appropriate pore diameter. In addition, the fiber saturation points (FSP) were determined by DSC. The former were performed in an isothermal-step method and the latter using the continuous heating-up method. Native and thermally modified twin samples of Norway spruce (Picea abies (L.) Karst.), Sycamore maple (Acer pseudoplatanus L.) and European ash (Fraxinus excelsior L.) were analyzed. The results clearly show that the pore shares of wood for the measurable diameter range between 4 and 400 nm decrease considerably in all studied wood species due to thermal modification of the wood. Furthermore, thermal modification of wood leads to a decreased FSP for all studied wood species. For evaluation as well as reproducibility of the results of pore-size distribution and FSP, the consideration of sensible heat and specific heat of fusion plays an important role. If this is not done, it can lead to misinterpretations. 相似文献
20.
A study was established to evaluate several management practices for improving American sycamore (Platanus occidentalis L.) establishment on land subjected to daily paper-mill sludge spray irrigation, and where a dense herbaceous cover dominated by pokeweed (Phytolacca americana L.) was nearly 2 m tall. Treatments studied included: two sludge application treatments (spray vs no spray), five weed control treatments (control, hand-release, oxyfluorfen, glyphosate and atrazine, and sulfometuron methyl), and two tree shelter treatments (control vs tree shelter). Survival and growth of sycamore seedlings were evaluated after one growing season. Sludge application treatment had the greatest effect on tree survival; survival was greatest on plots that were not sprayed during the year of tree growth. Among the weed control treatments, the hand-release treatment resulted in best survival; survival was 100% when hand release was used on unsprayed plots. Tree shelters provided no benefit to tree establishment. 相似文献
|