scholarly journals Seedling height and the impact of harvesting operations on advance regeneration of conifer species in upland Britain

2009 ◽  
Vol 82 (2) ◽  
pp. 185-198 ◽  
Author(s):  
V. Stokes ◽  
G. Kerr ◽  
D. Ireland
Keyword(s):  
Seedling Height ◽  
Conifer Species ◽  
Advance Regeneration ◽  
The Impact

Establishment of natural regeneration under severe browsing pressure from white-tailed deer after group seed-tree cutting with scarification on Anticosti Island

2009 ◽  
Vol 39 (3) ◽  
pp. 596-605 ◽  
Author(s):  
Julien Beguin ◽  
Marcel Prévost ◽  
David Pothier ◽  
Steeve D. Côté
Keyword(s):  
Negative Impact ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
White Birch ◽  
Conifer Species ◽  
Double Pass ◽  
Advance Regeneration ◽  
Anticosti Island ◽  
The Impact ◽  
Tree Group

The use of large clearcuts with protection of advance regeneration is inappropriate for regeneration of balsam fir ( Abies balsamea (L.) Mill.) under severe browsing from white-tailed deer ( Odocoileus virginianus (Zimmermann)). However, little is known about the effects of tree-retention methods along with scarification on the establishment of balsam fir in a context of severe herbivory. Consequently, we hypothesized that seed-tree-group cutting in conjunction with soil scarification creates favourable conditions for balsam fir regeneration. In 1998 and 1999 we set up three circular forest groups of different sizes (40, 60, and 80 m in diameter) surrounded by three different intensities of scarification (no treatment, single pass, double pass) in two balsam fir stands on Anticosti Island, Quebec, Canada. Moreover, we used a network of fenced and unfenced regeneration plots to evaluate the impact of white-tailed deer browsing. The results showed that up to 7 years after harvest, seed-tree-group cutting did not improve the establishment of conifer species. Scarification had a negative impact on the abundance of conifer species, whereas white birch ( Betula papyrifera Marshall) density was significantly higher in areas scarified twice than in unscarified areas. Overall, the development of palatable tree species appears unlikely at deer densities >20 individuals/km2.

Short-term effects of cut-to-length versus full-tree harvesting on conifer regeneration in jack pine, mixedwood, and black spruce forests in Manitoba

2004 ◽  
Vol 34 (9) ◽  
pp. 1938-1945 ◽  
Author(s):  
Isobel Waters ◽  
Steven W Kembel ◽  
Jean-François Gingras ◽  
Jennifer M Shay
Keyword(s):  
Picea Mariana ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Abies Balsamea ◽  
Jack Pine ◽  
Tree Regeneration ◽  
Understorey Vegetation ◽  
Advance Regeneration ◽  
The Impact

This study compares the effects of full-tree versus cut-to-length forest harvesting methods on tree regeneration in jack pine (Pinus banksiana Lamb.), mixedwood (Picea glauca (Moench) Voss – Populus tremuloides Michx. – Abies balsamea (L.) Mill.), and black spruce (Picea mariana (Mill.) BSP) sites in southeastern Manitoba, Canada. We surveyed tree regeneration densities, disturbance characteristics, and understorey vegetation in replicated control and harvested plots in each site type preharvest (1993) and 1 and 3 years postharvest (1994, 1996). In jack pine sites, the full-tree harvest method promoted regeneration of Pinus banksiana through increased disturbance of soil and the moss layer, and decreased slash deposition relative to the cut-to-length method. Conversely, in mixedwood sites the cut-to-length method resulted in less damage to advance regeneration and proved better at promoting postharvest regeneration of Abies balsamea and Picea glauca relative to the full-tree method. In black spruce sites, there were few differences in the impact of the two harvesting methods on regeneration of Picea mariana, which increased in frequency and density after both types of harvesting.

scholarly journals Effect of seedbed solarization on plant growth and yield of two rice varieties–BR11 and BRRI Dhan33

2017 ◽  
Vol 15 (1) ◽  
pp. 55-59
Author(s):  
MG Neogi ◽  
AKM Salah Uddin ◽  
MT Uddin ◽  
J Lauren
Keyword(s):  
Plant Growth ◽  
Stem Borer ◽  
Growth And Yield ◽  
Easy Access ◽  
Seedling Height ◽  
Main Field ◽  
Root Knot Nematode ◽  
Rice Varieties ◽  
Rice Season ◽  
The Impact

An experiment was carried out at RDRS Farm in Rangpur during the 2014 T. aman rice season to determine the impact of seedbed solarization on plant growth and yield of rice varieties, BR11 and BR33. Solarization was achieved by covering the seedbeds with transparent polythene sheet for four weeks prior to sowing. Seedlings of both varieties were raised on solarized and non-solarized seedbeds and later transplanted into the main field for comparison of growth and yield. Emergence, seedling height and weight, root length and weight were higher with seedlings raised on solarized seedbeds compared to seedlings from non-solarized seedbeds. Also root knot nematode galls decreased significantly on seedlings from solarized seedbeds compared to those from non-solarized seedbeds for both the varieties tested. The increase in height and weight of solarized seedlings enabled easy access for uprooting and transplanting seedlings in the main field within the recommended 20-25 days after sowing. When transplanted in untreated main fields, plants grown from the solarized seedlings of both the rice varieties had significantly less infestation of stem borer as compared to non-solarized plants. Grain yields obtained from solarized seedlings were 7% higher for BR11 and 9% higher for BR33 relative to normal seedlings.J. Bangladesh Agril. Univ. 15(1): 55-59, January 2017

scholarly journals The Use of Phytohormones in Production of Fruit Tree Rootstocks in Nursery Without Irrigation

2019 ◽  
Vol 67 (2) ◽  
pp. 463-470
Author(s):  
Jan Wolf ◽  
Tomáš Kiss ◽  
Rostislav Venuta ◽  
Tomáš Nečas
Keyword(s):  
Fruit Tree ◽  
The Other ◽  
Seedling Height ◽  
Crown Root ◽  
Other Hand ◽  
Root Thickness ◽  
Control Variant ◽  
The Impact

The most commonly used phytohormone to reduce the impact of drought is 24‑epibrassinolide (EBR). In this study, EBR was applied over two years on young rootstocks of peach (B‑VA‑1) and myrobalan (Vanovice myrobalan) seedlings. Young rootstocks were treated by EBR at different concentrations, IAA and a mixture of EBR with IAA. The best results in seedling height of Vanovice myrobalan in both years had the treatment of 0.05% IAA, 549.69 mm (2016) and 553.77 mm (2017). On the other hand, on the crown root thickness was affected the most in 2016 by treatment of EBR 0.06 ppm (5.5 mm) and in 2017 by EBR 0.01 ppm (7.5mm). At B‑VA‑1 rootstock, the highest seedlings in 2016 were measured after EBR + IAA treatment (1573.18 mm) and in 2017 after IAA treatment (682.75 mm). The highest thickness of the crown root was recorded in 2016 after EBR and IAA (17.76 mm) and in 2017 after EBR 0.1 ppm (8.08 mm) treatments. At more than half of the treatments the control variant was evaluated as a variant with the least satisfying results. According to the results EBR and IAA are possibly increasing the quality of the rootstocks in conditions of a nursery without an irrigation.

scholarly journals Postglacial migration across a large dispersal barrier outpaces regional expansion from glacial refugia: evidence from two conifers in the Pacific Northwest

2020 ◽  
Author(s):  
MC Fernandez ◽  
FS Hu ◽  
DG Gavin ◽  
G deLafontaine ◽  
KD Heath
Keyword(s):  
Climate Change ◽  
Pacific Northwest ◽  
Glacial Refugia ◽  
Conifer Species ◽  
Changing Climate ◽  
Modern Species ◽  
The Pacific ◽  
Postglacial Migration ◽  
The Impact

AbstractUnderstanding how climate refugia and migration over great distances have facilitated species survival during periods of past climate change is crucial for evaluating contemporary threats to biodiversity. In addition to tracking a changing climate, extant species must face complex, anthropogenically fragmented landscapes. The dominant conifer species in the mesic temperate forests of the Pacific Northwest are split by the arid rain-shadow of the Cascade Range into coastal and interior distributions, with continued debate over the origins of the interior populations. If the Last Glacial Maximum extirpated populations in the interior then postglacial migration across the arid divide would have been necessary to create the current distribution, whereas interior refugial persistence could have locally repopulated the disjunction. These alternative scenarios have significant implications for the postglacial development of the Pacific Northwest mesic forests and the impact of dispersal barriers during periods of climate change. Here we use genotyping-by-sequencing (ddRADseq) and phylogeographical modeling to show that the postglacial expansion of both mountain hemlock and western redcedar consisted largely of long-distance spread inland in the direction of dominant winds, with limited expansion from an interior redcedar refugium. Our results for these two key mesic conifers, along with fossil pollen data, address the longstanding question on the development of the Pacific Northwest mesic forests and contrast with many recent studies emphasizing the role of cryptic refugia in colonizing modern species ranges.Statement of SignificanceUnderstanding whether habitat fragmentation hinders range shifts as species track a changing climate presents a pressing challenge for biologists. Species with disjunct distributions provide a natural laboratory for studying the effects of fragmentation during past periods of climate change. We find that dispersal across a 50-200-km inhospitable barrier characterized the expansion of two conifer species since the last ice age. The importance of migration, and minimal contribution of more local glacial refugia, contrasts with many recent studies emphasizing the role of microrefugia in populating modern species distributions. Our results address a longstanding question on the development of the disjunct mesic conifer forests of the Pacific Northwest and offer new insights into the spatiotemporal patterns of refugial populations and postglacial vegetation development previously unresolved despite decades of paleoecological studies.

scholarly journals Effect of Different Moisture Harvesting Techniques on Seedling Survivals and Growth of Trees in Degraded Lands of Southern Tigray

2019 ◽  
pp. 1-10
Author(s):  
Gebru Eyasu Siyum ◽  
Tuemay Tassew ◽  
Abadi Gidey
Keyword(s):  
Survival Rate ◽  
Tree Species ◽  
Field Experiments ◽  
Tree Planting ◽  
Seedling Height ◽  
Tree Seedling ◽  
Degraded Lands ◽  
Tree Survival ◽  
Harvesting Techniques ◽  
The Impact

Tree planting on degraded lands play a key role in forest rehabilitation processes through afforestation and/or reforestation. Moisture harvesting structures (MHSs) has significant impact on seedling survivals at degraded lands. The objectives of this study were to investigate the impact of water harvesting techniques on seedling survival and growth performance of trees. Field experiments were conducted for two rainy seasons in southern Tigray, Atsela watershed. The experimental design followed was the split plot design. The MHSs as main plot used were eye-brow basins (EBs), micro trench (MTs), improved pit (IPs) and as control normal pit (NPs). The tree species grown as subplots were Eucalyptus camaldulensis, Grevillea robusta, Olea europaea and Cupressus lusitanica. The four tree species were planted by using seedlings. The tree survival rate, height, crown width (CW) and root collar diameter (RCD) of the four tree species were measured every six months after transplanting. The result shows that MHSs were significant in tree seedling height, CW and RCD but not in tree survival rate. Tree seedling height and CW grown in EBs were significantly higher than those grown in MTs, IPs and NP (P≤0.05). RCD of tree seedling was higher when grown in EBs than NP (control) (P≤0.05). The interaction of tree species seedlings and MHSs shows that those seedlings grown on MHSs were significantly thicker, taller and more survived than those grown on the NPs (control) (P≤0.05). So based on the experiments, it is concluded that MHSs particularly the eyebrow basin was considered as the most appropriate planting pit. Therefore, further demonstration of eyebrow basin tree planting should be carried out.

scholarly journals GERMINATION OF SUNFLOWER SEED IN DIFFERENT MEDIA

2020 ◽  
Vol 21 (supplement 1) ◽  
Author(s):  
Arshdeep Singh ◽  
Shimpy Sarkar ◽  
Jaspreet Kaur ◽  
Deepika Gundlee ◽  
Altaf Hussain ◽  
...  
Keyword(s):  
Sunflower Seed ◽  
Germination Rate ◽  
Seedling Emergence ◽  
Seedling Height ◽  
Seedling Production ◽  
Sand Soil ◽  
Sunflower Crop ◽  
Number Of Leaves ◽  
The Impact ◽  
Germinated Seeds

A study was carried out at Lovely Professional University, Phagwara (Punjab) with the aim to evaluate the impact/s of substrates on the germination and seedling emergence of sunflower, an ornamental flower crop. The ornamental sunflower crop is gaining popularity in recent times because the gestation period of investment on this crop is very short, moreover it has expressive representation in the flower market and the research on the idea to substrate for seedling production to increase the information for the crop. The experiment has been conducted in a polyhouse, where they were put to germinate seed of sunflower type Sadabahar sunflower F-1 Hybrid in the polysterene trays on substrates. The experiment was conducted with seven different media viz. sawdust, sand, soil, sawdust + sand (1:1), sawdust + soil (1:1), sand + soil (1:1), sawdust + sand + soil (1:1:1). Germinated seeds were counted daily over a period of 15 days. To estimate the seedling emergence from two weeks after sowing up to four-week, data on seedling height and number of leaves were recorded. The result showed that germination started in 8 days after sowing for all the substrates. The highest germination rate was recorded on sawdust substrates (83%), while the lowest rate (55%) on soil seedling on the sawdust substrates had maximum 5 leaves.

scholarly journals The Impact of Drought and Vascular-Inhabiting Pathogen Invasion inPinus taedaHealth

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Pratima Devkota ◽  
Scott A. Enebak ◽  
Lori G. Eckhardt
Keyword(s):  
Abiotic Factors ◽  
Fine Root Biomass ◽  
Lesion Length ◽  
Severe Drought ◽  
Seedling Height ◽  
Pathogen Invasion ◽  
Moderate Drought ◽  
Leptographium Terebrantis ◽  
Combined Impact ◽  
The Impact

The complex interaction of various biotic and abiotic factors may put the overall stand health ofPinusspp. at risk. A study was designed to determine the combined impact of drought and vascular-inhabiting fungi (Leptographium terebrantisandGrosmannia huntii) inPinus taeda. Seedlings from twoP. taedafamilies were planted and watering treatments, (i) normal watering, (ii) moderate drought, and (iii) severe drought, were applied. One month following the initiation of watering treatments, seedling stems were artificially inoculated withL. terebrantisandG. huntii. Drought and fungal interaction significantly affected lesion length/seedling height, occlusion length/seedling height, and seedling fine root biomass.Leptographium terebrantiswas more pathogenic under moderate and severe drought than normal watering condition, whereas the pathogenicity ofG. huntiiremains unaltered. The susceptibility of the families to vascular-inhabiting fungi remained the same under different watering treatments. Drought and specific vascular-inhabiting fungi may negatively impactP. taedastand health.

Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts

1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten
Keyword(s):  
Explosive Charge ◽  
The Moon ◽  
Meteorite Impacts ◽  
The Earth ◽  
Lunar Craters ◽  
The Impact

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.

The Geosciences Applied to Lunar Exploration

1962 ◽  
Vol 14 ◽  
pp. 169-257 ◽  
Author(s):  
J. Green
Keyword(s):  
Lunar Surface ◽  
Probable Mechanism ◽  
Point Of View ◽  
Lunar Exploration ◽  
Geological Model ◽  
Apply Geophysics ◽  
Surface Features ◽  
The Impact

The term geo-sciences has been used here to include the disciplines geology, geophysics and geochemistry. However, in order to apply geophysics and geochemistry effectively one must begin with a geological model. Therefore, the science of geology should be used as the basis for lunar exploration. From an astronomical point of view, a lunar terrain heavily impacted with meteors appears the more reasonable; although from a geological standpoint, volcanism seems the more probable mechanism. A surface liberally marked with volcanic features has been advocated by such geologists as Bülow, Dana, Suess, von Wolff, Shaler, Spurr, and Kuno. In this paper, both the impact and volcanic hypotheses are considered in the application of the geo-sciences to manned lunar exploration. However, more emphasis is placed on the volcanic, or more correctly the defluidization, hypothesis to account for lunar surface features.

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