scholarly journals A Mapping of the Present and Past Forest-types of Prince Edward Island

2004 ◽  
Vol 118 (4) ◽  
pp. 504 ◽  
Author(s):  
D. G. Sobey ◽  
W. M. Glen

Our aim was to produce maps showing the distribution on Prince Edward Island of five forest-types previously identified from a TWINSPAN analysis of ground flora data collected at 1200 sampling points in a field survey. For this purpose we had available two databases: one on the composition of the tree canopy of 82,957 forest stands, as determined by photointerpretation of a 1990 aerial photographic survey of the island; the other on the drainage properties of the same stands from a published soil survey. The tree canopy and drainage criteria for sorting these stands into five stand-types were chosen in the light of the equivalent properties of the TWINSPAN forest-types as evident from the field survey. These criteria were perfected in four trial computer-sortings, followed by the computer-printing of maps showing the distribution of the standtypes. These maps, which were then evaluated by comparing them with the properties of the TWINSPAN forest-types, are the first fine-scale maps of the main forest-types of the island. They reveal that, of the three “primary” forest-types, the upland hardwood forest occurs especially in the central and south-eastern hill-lands, as well as in scattered parcels elsewhere, whereas the Black Spruce forest and the wet species-rich woodland occur primarily in areas of lower elevation in the east and west of the island. The two forest-types resulting from human disturbance, the White Spruce woods and the “disturbed forest”, have a more scattered distribution, with the White Spruce woods being found especially in the central and eastern parts of the island and the disturbed forest in the west and east of the island. A secondary aim was to map the conjectured distribution before European settlement of the three primary forest-types: two maps have been produced, one showing the distribution of upland hardwood forest, the other of the wet forest-types.

2006 ◽  
Vol 30 (4) ◽  
pp. 363-369 ◽  
Author(s):  
M.K. Mahendrappa ◽  
C.M. Pitt ◽  
D.G.O. Kingston ◽  
T. Morehouse

Oryx ◽  
2002 ◽  
Vol 36 (2) ◽  
pp. 133-139 ◽  
Author(s):  
Stefanie Heiduck

The masked titi Callicebus personatus melanochir is a threatened primate, endemic to the Atlantic rainforest of eastern Brazil. The Atlantic rainforest has been reduced to only 5% of its former extent, and only 2% consists of undisturbed forest. The survival of the masked titi monkey is therefore dependent on its ability to utilise disturbed forest habitat. A group of four masked titi monkeys was observed for one year in a plot that contained both disturbed and undisturbed forest. The group used a home range of 22 ha, which comprised 58% undisturbed forest, 31% selectively logged forest and 11% forest that was regrowing after a clear-cut. The titi monkeys did not use the different forest types in proportion to the availability of each within their home range: undisturbed forest was used more than expected from its proportional availability, and disturbed forest was used less than expected. Use of forest types appeared to be determined by the availability of food resources. Undisturbed forest had the most food per unit area and regrowing forest had the least. This study shows that masked titi monkeys may be able to survive in disturbed forest habitats if these areas are of high enough quality to contain sufficient food and other resources.


2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Do Thi Ngoc Le ◽  
Nguyen Van Thinh ◽  
Nguyen The Dung ◽  
Ralph Mitlöhner

The effects of disturbance regimes on the spatial patterns of the five most abundant species were investigated in three sites in a tropical forest at Xuan Nha Nature Reserve, Vietnam. Three permanent one-ha plots were established in undisturbed forest (UDF), lightly disturbed forest (LDF), and highly disturbed forest (HDF). All trees ≥5 cm DBH were measured in twenty-five 20 m × 20 m subplots. A total of 57 tree species belonging to 26 families were identified in the three forest types. The UDF had the highest basal area (30 m2 ha−1), followed by the LDF (17 m2 ha−1) and the HDF (13.0 m2 ha−1). The UDF also had the highest tree density (751 individuals ha−1) while the HDF held the lowest (478 individuals ha−1). Across all species, there were 417 “juveniles,” 267 “subadults,” and 67 “adults” in the UDF, while 274 “juveniles,” 230 “subadults,” and 36 “adults” were recorded in the LDF. 238 “juveniles,” 227 “subadults,” and 13 “adults” were obtained in the HDF. The univariate and bivariate data with pair- and mark-correlation functions of intra- and interspecific interactions of the five most abundant species changed in the three forest types. Most species indicated clumping or regular distributions at small scale, but a high ratio of negative interspecific small-scale associations was recorded in both the LDF and HDF sites. These were, however, rare in the UDF.


2011 ◽  
Vol 233-235 ◽  
pp. 2528-2531 ◽  
Author(s):  
Xi An Li ◽  
Qiang Xu ◽  
Hong Zhou Lin ◽  
Wan Jun Ye

Sub-ground erosion often resulted in severe problems in various engineering constructions, most of which is due to the sub-erosion in loess. In this paper, the critical condition of “soil bursting” was analyzed and the formula describing the critical condition of soil bursting was derivated by the analytical method. Furthermore, the velocity of tunnel-erosion in loess and its influential factors were studied. A set of tests are designed to study the relationship between the tunnel-erosion velocity and the key influential factors. The key factors considered in the test include soil density as well as the initial water content. The other purpose is to reveal the characteristics of the tunnel-erosion process. Phenomena observed during the tests together with the data from field survey revealed the mechanism of tunneling in loess very well, and the work in this paper formed a theoretical basis for further study about sub-ground erosion in loess.


2004 ◽  
Vol 82 (10) ◽  
pp. 1518-1538 ◽  
Author(s):  
Christine Roberts ◽  
Oluna Ceska ◽  
Paul Kroeger ◽  
Bryce Kendrick

Over 5 years, macrofungi from six habitats in Clayoquot Sound, Vancouver Island, British Columbia, were documented. Habitats were categorized as dune, spruce fringe, old-growth rainforest, second-growth forest, bog, or estuarine. All but the second-growth forest are natural ecosystems. A total of 551 taxa of macrofungi were recorded. Between 17% and 36% of the species in any one habitat were found only in that habitat. The most frequently encountered and ubiquitous species was Craterellus tubaeformis (Fr.) Quel., found in all years, habitats, and sites. Of the 551 taxa, only 28 were found every year, and 308 were found in only 1 year. Rare species that were recorded include Cordyceps ravenelii Berkeley & Curtis, Hygrophorus inocybiformis Smith, and Tricholoma apium Schaeffer in the dunes and Stereopsis humphreyi (Burt) Redhead in the spruce fringe. Similarities between habitats based on taxa in common showed that bog and estuarine habitats had only 9%–17% in common with each other and the other habitats, whereas dune, spruce fringe, and the two forest types shared 21%–31% of their species. Old-growth rainforest yielded approximately 4 times as many species as bog and estuarine habitats, and approximately 1.5 times as many as the other three habitats.Key words: Clayoquot Sound, Vancouver Island, macrofungi, habitats, biodiversity.


1960 ◽  
Vol 40 (4) ◽  
pp. 721-728
Author(s):  
D. C. Read

Experiments in 1958 and 1959 with pre-planting soil treatments of insecticides, applied in a 5-inch band [Formula: see text] below the seed in ridges of soil, snowed that heptachlor, aldrin and chlordane, each at 5 pounds toxicant per acre, gave 70 to 90 per cent reduction in root maggot damage in cruciferous crops in Prince Edward Island. Each of these insecticides gave better control of the second than of the first generation of root maggots. Nematocide 18,133, at 5 and at 10 pounds per acre gave complete control throughout the growing season and also gave the highest yield. Thimet at 5 and at 10 pounds gave better control than the chlorinated hydrocarbons; parathion and Guthion, at the same rates, gave better control of the first generation but not as effective control thereafter. Korlan at 6 pounds gave fair control of the first generation but was ineffective thereafter. Ethion, Trithion, Di-syston and Diazinon, each at 5 and at 10 pounds, and Co-Ral and Dylox at 5 pounds were ineffective in controlling root maggot injury. Diazinon was highly phytotoxic; none of the other insecticides showed any phytotoxicity.


1988 ◽  
Vol 68 (2) ◽  
pp. 381-394 ◽  
Author(s):  
J. W. FYLES ◽  
W. B. McGILL

It was hypothesized that topographic location, fire, species characteristics, and soil texture interacted to maintain stable vegetation patterns on the landscape. As a corollary, relationships would exist between specific vegetation and profile development patterns, they would not be masked by secondary succession, and they would explain the distribution of both plant communities and soil types in the landscape. This hypothesis was tested in a study of soils and vegetation at eight sites representing three forest types (pine/lichen; closed canopy jack pine; white spruce) on sand ridges near the town of Slave Lake, Alberta. Differences in profile characteristics among soils studied corresponded to differences in vegetation. Soils under white spruce and jack pine/alder forest showed evidence of greater translocation of amorphous iron and aluminum than soils under jack pine/lichen woodland. The fractionation of phosphorus among organic, Ca–, Al–, and Fe– phosphates differed between soils under the three forest types as did the development of a textural B horizon. Clay eluviation appeared to be dependent primarily on initial clay content of the parent material although a contributory influence of vegetation was suggested. Integration of processes involved in soil profile development with those controlling vegetation dynamics particularly fire behavior, appears to provide a conceptual basis for explaining the distribution of soils in the landscape of the study area. Key words: Central Alberta, vegetation, sandy soils, eluviation, phosphorus fractions, soil development, fire


2018 ◽  
Vol 2 (4) ◽  
pp. 67 ◽  
Author(s):  
Sina Heshmati ◽  
Mohammad Mazloomi ◽  
Philip Evans

Machining grooves into the surface of pine and fir (Abies spp.) deckboards reduces undesirable checking that develops when “profiled” boards are exposed to the weather. We aim to develop improved profiles for Douglas fir, western hemlock and white spruce decking to reduce their susceptibility to checking, and understand how profile geometry influences the stresses that cause checking. We varied the width and depth of grooves in profiled deckboards, exposed deckboards to the weather, and measured checking and cupping of boards. A numerical model examined the effect of groove depth on the moisture-induced stresses in profiled spruce boards. Profiling significantly reduced checking, but increased cupping of deckboards made from all three species. Western hemlock checked more than the other two species. Profiles with narrow grooves (rib profiles) were better at restricting checking than profiles with wider grooves. A rib profile with deeper grooves developed smaller stresses than a rib profile with shallower grooves, and boards with the former profile checked less than boards with shallower grooves. We conclude that checking of profiled Douglas fir, western hemlock and white spruce decking is significantly reduced by changing profile geometry, and our results suggest the best profiles to reduce checking of all three species.


1986 ◽  
Vol 3 (1) ◽  
pp. 16-18 ◽  
Author(s):  
John Zasada ◽  
Rodney Norum

Abstract Broadcast burning following harvesting on flood-plain sites in Alaska substantially decreased residual organic material and increased exposed mineral soil. Two forest types were studied: white spruce/alder/feathermoss and white spruce/alder/lingenberry/feathermoss. The latter site contained permafrost. Fuel was reduced 67% and 81%, respectively; organic horizon thickness was decreased 43% to 2.9 in (7.4 cm) and 55% to 2.5 in (6.4 cm), respectively; and mineral soil exposure was 13% and 8%, respectively. Burning created good conditions for planting on both types. In addition, mechanical site preparation to increase mineral soil exposure appears to be necessary to achieve adequate, well-distributed regeneration from seed. North. J. Appl. For. 3:16-18, Mar. 1986.


2004 ◽  
Vol 34 (8) ◽  
pp. 1766-1775 ◽  
Author(s):  
G J Jordan ◽  
M J Ducey ◽  
J H Gove

We present the results of a timed field trial comparing the bias characteristics and relative sampling efficiency of line-intersect, fixed-area, and point relascope sampling for downed coarse woody material. Seven stands in a managed northern hardwood forest in New Hampshire were inventoried. Significant differences were found among estimates in some stands, indicating a potential for difference in bias in field implementation of the methods. In terms of relative sampling efficiency, results for each method varied among stand. However, point relascope sampling had comparable or better time efficiency than the other methods in most stands.


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