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1.
The relative influence of seed and microsite availability in the seedling emergence and recruitment of Liaodong oak (Quercus wutaishanica), which dominates the native hardwood forest in Loess Plateau, was examined by seed sowing experiments. Experiments were
performed in 216 plots (30 × 30 cm), located in three typical stands (Pinus tabulaeformis plantation, Liaodong oak forest and grassland, 72 plots per stand). A seed augmentation experiment was performed in an oak
forest and a conifer plantation, and a seed introduction experiment was carried out in a grassland. Three main factors were
considered: seed addition, disturbance and shrub cover. The seedling number and growth in every plot were recorded continuously
over 3 years. GLM multivariate was used to analyze the relationships between seedling emergence/recruitment and the explanatory
variables in every stand. The results showed that seed addition in undisturbed or disturbed plots always caused significantly
increased seedling emergence and recruitment in oak and conifer forests. It demonstrated that the recruitment of Liaodong
oak was limited by seed and microsite availability under closed forest, and litter is one of the factors leading to microsite
limitation. However, in the grassland, no treatments improved recruitment, indicating that the grassland was not suitable
for seedling recruitment because of intense light and soil drought. In the conifer forest, more recruited seedlings, and lower
herbivory on seedling leaves, as well as thicker stem basal diameters, indicated that the P. tabulaeformis plantation was safer for Liaodong oak seedling establishment. Unexpectedly, shrub cover did not affect the recruitment of
Liaodong oak in the three stands. 相似文献
2.
Fall fertilization of Holm oak affects N and P dynamics,root growth potential,and post-planting phenology and growth 总被引：2，自引：0，他引：2
Juan A. Oliet José M. Salazar Rafael Villar Eduardo Robredo Fernando Valladares 《Annals of Forest Science》2011,68(3):647-656
• Introduction
For Holm oak (Quercus ilex L.), a flush growing species, nutrient loading during the growing season is difficult and can lead to a low nutrient status of the seedlings. To provide insights about Holm oak nutrient dynamics during fall in the nursery and subsequent planting performance, a factorial nursery experiment was conducted in a mild fall–winter area testing the effects of timing of fertilization (early and late fall) and rate (two doses of a NPK fertilizer that applied 28 and 56 mg N per seedling), followed by an experimental plantation. 相似文献3.
Introduction
We examined the functional relationship between seed size and seedling performance in the valley oak (Quercus lobata Née) by means of a 13-year common garden experiment. 相似文献4.
Jean-Baptiste Morisset Frédéric Mothe Bruno Chopard Didier François Florence Fontaine Francis Colin 《Annals of Forest Science》2012,69(2):139-152
• Context
While past studies on epicormics in oak (Quercus sp.) have focused on the effect of thinning on epicormic shoots emergence, the consequences of this emergence on the epicormic ontogeny and future wood quality have rarely been asked. 相似文献5.
M. C. Rodríguez‐Molina L. M. Torres‐Vila A. Blanco‐Santos E. J. Palo Núñez E. Torres‐Álvarez 《Forest Pathology》2002,32(6):365-372
The emergence and survival of pregerminated holm oak (Quercus ilex) and cork oak (Quercus suber) acorns from two ecologically different dehesas (Mediterranean open woodlands) were studied in two soils from these stands naturally infected with Phytophthora cinnamomi, and in the same soils previously sterilized in the autoclave. Phytophthora cinnamomi was consistently isolated from the radicles of all unemerged and all emerged but dead seedlings from the unsterilized substrates. Seedlings of holm oak were more susceptible to P. cinnamomi than those of cork oak. Mortality of holm oak seedlings was significantly different depending only on soil treatment (sterilized or unsterilized), and it was 100% in unsterilized soils, independent of acorn provenance and soil origin. Mortality of cork oak seedlings was significantly different depending on the acorn origin and soil treatment, and on the interactions acorn origin × soil origin and soil origin × soil treatment. The demonstrated high susceptibility of holm and cork oak young seedlings to P. cinnamomi could be a limiting factor in Mediterranean open woodlands (dehesas) not only in natural regeneration processes but also when reforestation by direct sowing is implemented. 相似文献
6.
《Scandinavian Journal of Forest Research》2012,27(4):308-317
Abstract The effects of fencing and site preparation on performance of birch (Betula pendula Roth), oak (Quercus robur L.), pine (Pinus sylvestris L.) and spruce [Picea abies (L.) Karst.] seedlings were studied over four growing seasons in southern Sweden. The experiment was composed of four browsing treatments, from which roe deer (Capreolus capreolus L.) were excluded for 0, 12, 24 or 42 months, and four soil treatments. Natural browsing was combined with artificial browsing (clipping). It was demonstrated that browsing by roe deer could be isolated from browsing by moose (Alces alces L.) by selective fencing. Except for birch, browsing had little effect on seedling survival. Browsing reduced height growth by more than 100% for oak and pine, and more than 60% of pine seedling developed multiple stems. Except for oak, site preparation increased seedling survival. Inverting site preparation, in combination with or without fertilization, produced positive growth responses in seedlings, whereas patch scarification did not. There was no interaction between browsing and soil treatments on seedling performance. It was concluded that long-term protection against browsing by roe deer is needed for oak and pine, whereas short-term fences might be used for birch, and that spruce is relatively unaffected by browsing. 相似文献
7.
Compared with conventional planting, direct seeding of Quercus spp. is a method that can reduce the costs of reforestation considerably. However, interference from natural vegetation and predation on acorns contribute to regeneration failures. Mechanical site preparation has the potential to reduce both these problems. To study the influence of sowing date and of different mechanical site preparation treatments on early seedling growth, an experiment was carried out in storm-felled areas, formerly Norway spruce forests, in southern Sweden from May 2006 to September 2008. Five treatments were applied and acorns were planted in May and July 2006. The treatments were: disc trenching, patch scarification, topsoil removal, mounding and an undisturbed control. A delay of less than two months in seeding resulted in the equivalent of one year's growth reduction with respect to oak seedling's height and biomass. This could be explained by delayed emergence of seedlings, and by the dry conditions during summer seeding. The seedlings only exhibited a weak positive biomass growth response following disc trenching, patch scarification and top soil removal. In the latter case this might be explained by increased soil compaction and extensive removal of the humus layer. Site preparation by mounding resulted in good vegetation control, an increased biomass growth response and deeper seedling roots. In this treatment, we found high relative light levels near seedlings, reduced soil moisture and dry bulk density of the soil and higher soil temperatures. One or more of these environmental factors could have influenced the growth response. Whether this increased early growth rate persists throughout young stand development is, however, uncertain. 相似文献
8.
Hiroki Itô 《Journal of Forest Research》2009,14(4):245-250
Seedling emergence and initial survival were compared for two evergreen broad-leaved species, Quercus glauca and Symplocos prunifolia. The relationships between the two seedling dynamics variables and environmental factors for the two species were also investigated.
The number of seedlings that emerged in the study period was larger for S. prunifolia than for Q. glauca, while the survival rate was lower for S. prunifolia, presumably due to the closed canopy of this site. Models were selected for each species to determine the combination of
variables explaining the most variation in emergence and survival of seedlings. The model selected for seedling emergence
of Q. glauca showed that more seedlings emerged in lower hillslope positions and where the canopy in winter was more open. The model selected
for S. prunifolia showed that fewer seedlings emerged on steeper slopes and that more emerged under a more open canopy in winter. With respect
to seedling survival, models with only the proportion of open canopy in summer were selected for both species. These models
showed that the survival rate was higher where the canopy in summer was more open. This is to be expected as both species
are regarded as pioneer or mid-successional species. Q. glauca seemed to have the ability to persist as a dominant in the secondary forest at this site for longer than S. prunifolia due to the former’s better seedling survival rates and the rarity of climax species such as Castanopsis cuspidata. 相似文献
9.
J. J. Zhu Z. G. Liu H. X. Wang Q. L. Yan H. Y. Fang L. L. Hu L. Z. Yu 《New Forests》2008,36(3):247-260
Larix olgensis is one of the important commercial timber tree species in northeastern China, but it does not naturally regenerate in L. olgensis forests even after cutting. To identify the causes of the regeneration failure, the authors tested the effects of site preparation
in a thinned stand and in a clearcut on the emergence and early establishment of L. olgensis seedlings. The results indicated that there was no correlation between cumulative emergence percentage (CEP) of L. olgensis seedlings and canopy openness, but the CEP was significantly affected by site preparation (P < 0.001). The average seedling survival rates after treatments consisting of removing both litter cover and understory vegetation
cover were significantly higher in the clearcut than in the thinned stand (P < 0.001). Without site preparation, all seedlings in both the thinned stand and the clearcut disappeared within the first
growing season, meaning that ground cover (understory vegetation cover and litter cover) was not beneficial to seedling survival.
The average growth of seedlings exhibited significant differences between the thinned stand and the clearcut, and among the
site preparations (P < 0.001). Intensely thinned stands without ground cover improved seedling growth. These results imply that light and ground
cover might be the main factors limiting the early establishment of L. olgensis seedlings in managed plantation forests 相似文献
10.
The limited success of methods to naturally regenerate northern red oak (Quercus rubra L.) has increased the use of artificial techniques to improve overall oak composition. Enrichment plantings are often recommended
as a means to supplement species composition within the existing natural reproduction. Previous enrichment efforts have often
resulted in low survival and poor growth, generally due to poor planting stock quality and a lack of competition control.
In this study, high quality northern red oak seedlings were established on four recently harvested sites in western North
Carolina using one of four competition control treatments (untreated, year 1 control, year 2 control or a weed mat) in a 1.2 × 1.2 m
area around each seedling with or without a soil fertility amendment. The 3 year results show that competition control and
fertilization treatments had few positive impacts on survival and growth of the planted seedlings. These results suggest that
either the treatment area was insufficient to adequately release the seedlings, or other factors like belowground competition
from existing advance reproduction and/or stump sprouts may be important determinants of the overall success of northern red
oak enrichment plantings on recently harvested sites. 相似文献
11.
Manipulation of the canopy cover and site preparation are the most important silvicultural measures to enhance the conditions
for natural regeneration of Norway spruce (Picea abies (L.) Karst.). During the early regeneration phase however, seedling mortality may be high, so it is important to study how
different combinations of stand-level treatments and site preparation methods affect seedling establishment. We studied emergence,
1st winter and 2nd summer mortality for naturally regenerated spruce seedlings in a field experiment that combined four harvest
treatments (shelterwoods of high (SH), medium (SM) and low (SL) residual basal area, and a 50 × 50 m clear-cut (CC)) and two
site preparation methods (patch scarification and inverting). The CC had significantly fewer seedlings the 1st fall than the
SL and SH (p = 0.0377), and in all harvest treatments, fewer seedlings emerged in inverted than in patch scarified spots (p = 0.0351). Mortality was also lower with patch scarification than inverting (1st winter: p = 0.0565, 2nd summer: p = 0.0377), but was not affected by harvest treatment (1st winter: p = 0.9211, 2nd summer: p = 0.1896). On average, mortality from 1st to 2nd fall reached 38% and 27% after inverting and patch scarification, respectively.
First winter mortality accounted for approximately two thirds of the accumulated mortality, regardless of the harvest treatment
and site preparation method. 相似文献
12.
Jacob Royse Mary A. Arthur Angela Schörgendorfer David L. Loftis 《Forest Ecology and Management》2010
Recurrent problems with regeneration of oaks (Quercus spp.) have been documented across a wide range of ecosystems. In oak-dominated forests of the central and Appalachian hardwood regions of the United States, a lack of competitive oak regeneration has been tied, in part, to fire suppression in these landscapes, and managers throughout the region are using prescribed fire to address this concern. To examine fire effects on oak regeneration, researchers have generally relied on inventories or population studies of existing seedlings. These studies are valuable but do not permit examination of the role of fire in enhancing the establishment and growth of new oak seedlings stemming from oak mast events. In this study, white (Quercus alba) and chestnut oak (Quercus prinus) acorn mast crops serendipitously occurred in year three (fall 2005) of a landscape-scale prescribed fire experiment. We examined establishment, survival, height and diameter of new seedlings on sites on the Cumberland Plateau in eastern Kentucky. Treatments were fire exclusion, a single prescribed fire (1x-burn; 2003), and repeated prescribed fire (3x-burn; 2003, 2004, and after acorn drop in 2006), all conducted in late spring. Initial densities of newly established chestnut and white oak seedlings were statistically similar across treatments (P = 0.42), despite fires on the 3x-burn site having occurred after acorns were on the ground. Oak seedling density was significantly predicted by oak basal area on all sites (R2 = 0.12–0.46), except for chestnut oak on fire-excluded sites (R2 = 0.04). Litter depth was less on 3x-burn sites compared to 1x-burn and fire-excluded sites, whereas canopy openness was greater on both burn treatments compared to fire-excluded sites. Seedling mortality was generally higher on fire-excluded sites compared to burn sites, especially for white oak. Oak seedling mortality in the first two growing seasons was significantly predicted by initial litter depth and open sky, with greater litter depth and lower percent open sky leading to higher mortality. In the third growing season none of the measured variables predicted chestnut oak seedling survival; for white oak, percent open sky remained a significant predictor of mortality. Initially, seedlings on the fire-excluded sites had similar height but smaller diameter; after three growing seasons there were few differences in seedling height or diameter among treatments. Our findings suggest a potential role for prescribed fire in establishing forest floor and light conditions that may enhance the success of new oak germinants, although different responses among species may suggest the need to target management for individual oak species. 相似文献
13.
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.
Mar��a Jos�� Leiva Juan Manuel Mancilla-Leyton ��ngel Mart��n-Vicente 《Annals of Forest Science》2013,70(1):11-20
Context
??Dehesas?? are savanna-like ecosystems of human origin that extend broadly in the Mediterranean area of the Iberian Peninsula. They consist of scattered oaks (mainly Quercus ilex subsp. ballota L. holm-oak), an annual grassland layer and interspersed shrubs. These ecosystems, used for grazing and wild game, support high plant and animal biodiversity and provide important environmental services. At present, Mediterranean ??dehesas?? are endangered by the lack of oak regeneration.Aims
This paper analyses the efficiency of: (1) using shrubs as nurse plants; (2) drip irrigation of seedlings during summer; and (3) a combination of the two methods for the restoration of a ??dehesa?? in a mid-mountain Mediterranean area of southern Spain.Methods
Different techniques were tested to improve the recruitment of holm-oak seedling during a 3-year field experiment: (1) acorn plantation in open spaces, irrigating seedlings during the first dry season; (2) acorn plantation beneath the canopy of Myrtus communis L. and (3) both methods combined.Results
There was a large facilitative effect of myrtle for the recruitment of holm-oak seedlings, regardless of the supply of irrigation. This effect was associated with a large decrease in air temperature and photosynthetically active radiation beneath myrtle canopies. By contrast, summer irrigation of seedlings planted in open spaces did not improve seedling survival after 3 years despite a small and transient positive effect on seedling survival during the 1st year.Conclusion
The use of evergreen shrubs, such as myrtle, as nurse plants may be considered to restore ??dehesas?? instead of expensive seedling irrigation techniques. Several studies have promoted abandoning grazing to increase holm oak self-regeneration in ??dehesas??. However, creating closed patches of naturally occurring evergreen shrubs could provide suitable sites for oak planting when necessary, thus enhancing seedling recruitment without damaging the environmental and economic value of these ecosystems. 相似文献16.
Hatem Chaar Taher Mechergui Ali Khouaja Habib Abid 《Forest Ecology and Management》2008,256(4):722-731
Success of plantation establishment depends on the ability of seedlings to withstand animal browsing and competition from vegetation. This study in northwestern Tunisia examined the influence of browsing protection and vegetation control on seedling mortality, diameter, and height growth components of an evergreen sclerophyllous oak species, cork oak (Quercus suber L.) for the first 2 years after planting (2005 and 2006). Browsing protection was controlled by varying both treeshelter type (non-vented, vented, and control) and height (1.2-m and 1.8-m tall). Competing vegetation was controlled through increasing sizes of square-shaped black polyethylene mulch sheets: 0 m, 0.7 m, 1 m and 1.3 m large. Seedling mortality rate was relatively low during the first year (9%) and was not affected by any of the studied factors. During the following year, mortality was lower for seedlings in both types (non-vented and vented) of 1.2-m tall treeshelters than for unsheltered ones. Mortality was only slightly higher for 1.8-m tall shelters than for 1.2-m shelters. Compared to unsheltered seedlings, basal diameter was reduced during both seasons for seedlings inside non-vented treeshelters (1.2-m and 1.8-m tall), whereas for vented shelters it was reduced during the first year and then increased during the second year. Height growth was positively affected by tree shelters during both years. Seedlings inside non-vented 1.8-m tall shelters were the tallest having an average height of up to 140 cm at the end of the second year, while the unsheltered seedlings had only an average height of up to 42 cm. The greater height of the sheltered seedlings was attributed to the increase of: (1) the number of shoot flushes yearly established on the main stem (up to three), and (2) the length of all the growth units produced during each flush. Seedlings inside vented shelters had balanced growth with a low proportion of seedlings unable to support themselves without a stake (7%). However, non-vented shelters had unbalanced height and diameter growths resulting in both a higher height-to-diameter ratio and in a higher proportion of seedlings having stability problems (47%). Polyethylene mulch sheets did not affect early survival, seedling basal diameter, or number of shoot flushes established yearly, but did slightly improve seedling height at the end of the second season, mostly due to the significant improvement in shoot elongation of the first flush. Results suggest that both 1.8 m treeshelters and plastic mulches may enhance the growth of cork oak seedlings planted on harsh sites in northwestern Tunisia. 相似文献
17.
For establishment to be successful, planted oak must emerge above vegetative competition and browse level. A 3 year study
was established in 2000 in a cutover bottomland hardwood forest in west Alabama to examine the influences of seedling browse
protection and fertilizer use on growth of Nuttall oak (Quercus nuttallii Palm.) seedlings. The treatments included: control, 1.2 m tall wire tree shelter, and 1.2 m tall plastic tree shelter. Fertilizer
(20–10–5) was applied to one-half of all seedlings at planting. Competing vegetation was controlled around all seedlings with
mulch mats and herbicide. Fertilization did not affect height growth or successful establishment after 3 years. Four percent
of protected seedlings (plastic and wire tree shelters combined) were browsed compared to 95% of control seedlings. After
3 years, plastic tree shelters were the most effective treatment for promoting height growth and successful seedling establishment
of Nuttal oak seedlings (193 cm, 92.71% compared to 120 cm, 68.75% and 52 cm, 8.33% for wire tree shelter, and control seedlings,
respectively). Animal browse protection is deemed essential for successful seedling establishment in southern bottomland forests
where deer density is high (density estimated at 27 km−2 in vicinity of study area). 相似文献
18.
《Scandinavian Journal of Forest Research》2012,27(2):110-121
Seedling growth is often hampered on sites dominated by Kalmia angustifolia. In June 2000, a trial was established on a clear-cut site in Quebec, Canada, with a high cover of Kalmia and Vaccinium species. The objectives were to evaluate how soil scarification and fertilization at the time of planting influence early growth and establishment of black spruce [Picea mariana (Mill.) BSP] and jack pine (Pinus banksiana Lamb.) seedlings. During the first 2 years, scarification reduced Kalmia cover three-fold and doubled the distance from seedlings to the nearest Kalmia stem. Scarification did not increase soil-extractable NH4-N concentration, and reduced soil potassium, calcium and magnesium. Scarification had no effect on seedling water stress. Seedling growth improved and foliar nutrient concentrations were generally higher in scarified plots than in unscarified control plots. No differences were observed between single- and double-pass scarification for any variables except for ground-level stem diameter of seedlings, which was greater with double-pass scarification (12.1 vs 13.1 mm). Spot fertilization increased seedling growth and foliar nitrogen concentrations. Jack pine growth was greater than black spruce growth, an effect enhanced when seedlings were fertilized. 相似文献
19.
Despite the general practice of root pruning, little is known about the potential impact of reducing shoot/root systems of oak seedlings in this way on their future susceptibility to pathogens, for example Cylindrocarpon spp., Fusarium spp., Ilyonectria spp., Pythium spp. Phytophthora spp. or Rhizoctonia spp. In this study, root‐pruned and non‐pruned seedlings of Quercus robur grown under controlled conditions were inoculated with aggressive and less‐aggressive pathogens. Results indicated, in contrast to our initial assumption, that pathogens significantly reduced lateral root biomass more in non‐pruned seedlings, the extent of the response depending on the pathogens species. In response to pathogen pressure, pruned seedlings tended to attain a higher dry stem mass fraction, but lower dry leaf mass fraction. Pathogens also suppressed leaf mass in total root dry mass fraction (dry leaf mass/total root dry mass ratio, in g × g?1) more in pruned than in non‐pruned seedlings. These results suggest differences in growth between non‐pruned and pruned seedlings in response to pathogen stress. In nurseries, root pruning of oak trees may enhance the reduction in leaf mass in lateral roots mass fraction resulting from pathogen infections, which may decrease seedling quality. It is therefore important to ensure a low level of inoculum of soil‐borne pathogens to minimize the risk of seedling infection. 相似文献
20.
Anthony S. Davis Douglass F. Jacobs Kevyn E. Wightman Zonda K. D. Birge 《New Forests》2006,31(2):293-303
Bareroot hardwood seedling production involves intensive soil management. To increase soil organic matter (OM), nurseries
commonly grow a cover crop for 1 year after every 1–2 year of seedling production. Raising soil OM levels can also be achieved
through addition of soil amendments. We studied the influence of chicken manure (CM) and composted leaf, tree, and lawn trimmings
(Cp) on soil properties and morphology of green ash (Fraxinus pennsylvanica Marsh.) and northern red oak (Quercus rubra L.) seedlings. CM was applied at 725, 1450, or 2900 kg ha−1 (CM725, CM1450, and CM2900, respectively) and Cp was applied at 200 m3 ha−1. Addition of CM and Cp significantly raised soil OM levels and altered soil chemical properties compared to the control (Ctrl).
Root-collar diameter increased with addition of CM1450, CM2900, or Cp compared to CM725 or Ctrl plots for northern red oak,
but was largest in soils amended with CM2900 for green ash. Conversely, height was greatest with addition of CM725 for northern
red oak, but green ash seedlings were shorter in Ctrl plots than in all amendments except for CM725. Root volume of green
ash and northern red oak seedlings was positively influenced by addition of CM or Cp. Seedling responses to nursery soil amendments
vary with different forms and amounts of OM. Benefits to seedling growth through application of appropriate materials in the
proper balance can improve seedling morphological quality and positively influence soil chemical properties. 相似文献