A system using aerial photography to estimate area of root disease centers in forests

1978 ◽  
Vol 8 (2) ◽  
pp. 214-219 ◽  
Author(s):  
Ralph E. Williams ◽  
C. D. Leaphart

The area of root disease centers on the Coeur d'Alene National Forest in northern Idaho was effectively estimated from large-scale color infrared aerial photographs. An estimated 5.1% (12 160.7 ha) of the commercial forest land was occupied by infection centers. Root disease centers were identified in 113 of 364 stands actually surveyed. Although most of these 113 stands were of the Tsugaheterophylla – Pachistimamyrsinites habitat type, the highest percentage of stands with root disease was found in the Abiesgrandis – Pachistimamyrsinites habitat type.Observations made during these studies suggest that occurrence of Pseudotsugamenziesii (Mirb.) Franco, Abiesgrandis (Dougl.) Lindl., or both in a stand is the most important factor in the expression of root disease centers. Accuracy of interpretation of photographs was 92%; incorrect interpretations were consistently associated with stands in the Abieslasiocarpa series of habitat types or with stands stocked with conifers tolerant of root pathogens.

1990 ◽  
Vol 20 (7) ◽  
pp. 987-994 ◽  
Author(s):  
James W. Byler ◽  
Michael A. Marsden ◽  
Susan K. Hagle

Root disease killed trees in 33% of 579 stands on the Lolo National Forest, Montana. Of all the commercial forest land, 123 255 ha, or 18.8%, was diseased; 1.2% was in nonstocked patches. The statistical method CART (classification and regression trees) was used to construct a decision tree to place stands into one of four classes, based on the probability that the stands contained trees that were killed by root disease. High probabilities of root disease were found for stands in the western hemlock and grand fir habitat type series (0.59) and in other habitat types on moderate slopes with southerly aspects (0.48). Low probabilities of disease were found on non-hemlock and non grand fir types on northerly aspects (0.15) and southerly aspects that were on either flat or very rugged terrain (0.17). Both Phellinusweirii (Murr.) Gilb. and Armillaria sp., probably A. ostoyae (Romagna) Herick, were frequently associated with mortality in hemlock, grand fir, and cedar habitat type series. Only A. ostoyae was common on Douglas-fir and subalpine fir habitat type series, however. Selective harvest and fire control in these two classes may contribute to the extensive root disease mortality found in Lolo National Forest at present.


1984 ◽  
Vol 14 (5) ◽  
pp. 652-655 ◽  
Author(s):  
R. L. James ◽  
C. A. Stewart ◽  
R. E. Williams

Root disease losses were estimated on more than 3 million hectares of commercial forest land within seven national forests in the northern Rocky Mountains. Area estimates were made for root disease centers on all seven forests and scattered tree mortality on three forests. Tree mortality rate and associated volume loss were estimated for two forests. Approximately 31 600 ha (about 1% of the total commercial forest land) were occupied by large active disease centers discernable from large-scale aerial photographs on these forests. About 13% of the commercial forest land of three forests contained scattered root disease mortality of at least 3 trees/ha. About 35% of the annual tree mortality was associated with root diseases on two forests. Major root pathogens found were Armillariamellea and Phellinusweirii; bark beetles often infested root-diseased trees. Recommendations for improvement of survey techniques are discussed.


1982 ◽  
Vol 12 (4) ◽  
pp. 876-882 ◽  
Author(s):  
Ralph E. Williams ◽  
Michael A. Marsden

A data screening algorithm (SCREEN) identified stand age, average stand diameter, timber type, soil type, aspect, habitat type, and elevation as forest stand or site characteristics strongly associated with root-disease occurrence in northern Idaho forests. The logistic regression model was used to predict root disease center occurrence. A second algorithm (RISK) was used to compute the estimates for the coefficients and to test different prediction equations. On wet aspects, highest probability of root disease centers was found on soils with lowest year-round moisture availability. The reverse was true on dry aspects. Increased slope was associated with increased root disease. Root disease center frequency was inversely related to elevation and directly related to occurrence of Pseudotsugamenziesii (Mirb.) Franco and Abiesgrandis (Dougl.) Lindl. Expression of disease centers was maximum at 60–100 years of stand age on all habitat types. A habitat-type–age interaction was observed in oldest aged stands.


1996 ◽  
Vol 72 (1) ◽  
pp. 47-50 ◽  
Author(s):  
Tricia L. Wurtz ◽  
Anthony F. Gasbarro

The Native peoples of Alaska used wood for fuel, for the construction of shelters, and for a variety of implements. Explorers, fur traders, gold miners, and settlers also relied on Alaska's forest resource. The early 20th century saw the creation of the Tongass and Chugach National Forests in coastal Alaska, where large-scale harvesting began shortly after World War II. By 1955, two 50-year contracts had been signed, committing 13 billion board feet of sawlogs and pulpwood. The commercial forest land base in Alaska has been dramatically reduced by a variety of legislative acts, including the Statehood Act of 1959 and the Alaska National Interest Lands Conservation Act of 1980. Key words: forest history, Alaska, aboriginal use of forests, fuelwood, stemwheeled riverboats, gold mining, land classification, National Forests, Alaska Native Claims Settlement Act, Alaska National Interest Lands Conservation Act


1989 ◽  
Vol 4 (2) ◽  
pp. 52-54 ◽  
Author(s):  
David L. Verbyla ◽  
Richard F. Fisher

Abstract Forest habitat types have been purported to be useful indicators of site quality. This is generally true for habitat types with different dominant tree species. However, few have studied the site indicator value of habitat types with the same dominant tree species. We measured site index (base age 25) from 172 randomly selected plots within the ponderosa pine (Pinus ponderosa) zone of the Dixie National Forest, Utah. The range of site index within any one habitat type was broad. Poor sites occurred on all five habitat types. However, the best sites occurred only on the Pinus ponderosa/Symphoricarpos oreophilus and Pinus ponderosa/Quercus gambelii habitat types. Therefore, habitat type may be useful in predicting the best sites, but only if other site information is used in addition to habitat type. West. J. Appl. For. 4(2):52-54, April 1989.


1984 ◽  
Vol 14 (4) ◽  
pp. 523-527 ◽  
Author(s):  
G. W. Wallis ◽  
Y. J. Lee

Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands 15, 40, and 100 years of age containing root disease openings of various sizes were photographed using 70-mm Aerochrome color and color-infrared film at scales of 1:1 500 to 1:15 000. Success in detecting disease centers varied with scale relative to stand age and disease symptomatology. Scales of 1:6 000 provided adequate information for young stands 15–20 years of age whereas scales of up to 1:15 000 proved satisfactory for locating most centers in 100-year-old stands. The large variation in symptomatology among stands in the midage class made accurate assessment of disease occurrence difficult at all scales used. Measurement of area within most disease centers in a stand using aerial photographs is probably feasible only in mature stands. Color photographs were superior to color-infrared for detecting early foliage discoloration; the reverse was true when characterization of ground features and downed trees was desired.


Rangifer ◽  
1993 ◽  
Vol 13 (2) ◽  
pp. 71 ◽  
Author(s):  
René Nault ◽  
Carole Mathieu ◽  
Michel Crête

Ground coverage by woody and herbaceous plant species and standing biomass of vegetation susceptible to being grazed upon were estimated in a 156 km2 area where 190 muskoxen were censused during the preceding autumn. Habitat use was estimated with droppings census. Six terrestrial habitat types were delineated on 1:32 000 aerial photographs and randomly sampled: low shrub on xeric sites (LSX; 64 km2), low shrub on mesic sites (LSM; 45 km2), bare ground (BG; 27 km2), forest-tundra (FT; 12 km2), wet meadow (WM; 2 km2) and riparian willows (RW; 1 km2). Dominant plant species varied greatly between habitat types, and only a few such as Betula glandulosa, Salix arctophila, and Polygonum viviparum were common. Tall shrubs were present only in RW where they covered most of the ground, and in FT. Low shrubs were uniformly distributed and covered 18-32% of the ground, with the exception of RW (5%). Ground cover by herbs had a similar range (i.e. 20-37%), except in RW where the mean exceeded 50%. Mosses and lichens occupied about half of the ground everywhere. Phytomass exhibited great variation within and between habitat types; extreme values averaged 892 kg*ha-1 in LSX, and 1965 kg*ha-1 in LSM. However the difference was not significant due to limited sample size and within habitat variance. Nevertheless the mass of herbaceous dicots was greater in RW than in any other habitat type. Total phytomass was 2-20 times greater in northern Québec than in Greenland. Based on droppings density, muskoxen preferred RW over BG and FT, and LSX over BG. Although the density of muskoxen in the study area was high relative to other muskox ranges, habitat quality and quantity should allow continued population growth.


1996 ◽  
pp. 64-67 ◽  
Author(s):  
Nguen Nghia Thin ◽  
Nguen Ba Thu ◽  
Tran Van Thuy

The tropical seasonal rainy evergreen broad-leaved forest vegetation of the Cucphoung National Park has been classified and the distribution of plant communities has been shown on the map using the relations of vegetation to geology, geomorphology and pedology. The method of vegetation mapping includes: 1) the identifying of vegetation types in the remote-sensed materials (aerial photographs and satellite images); 2) field work to compile the interpretation keys and to characterize all the communities of a study area; 3) compilation of the final vegetation map using the combined information. In the classification presented a number of different level vegetation units have been identified: formation classes (3), formation sub-classes (3), formation groups (3), formations (4), subformations (10) and communities (19). Communities have been taken as mapping units. So in the vegetation map of the National Park 19 vegetation categories has been shown altogether, among them 13 are natural primary communities, and 6 are the secondary, anthropogenic ones. The secondary succession goes through 3 main stages: grassland herbaceous xerophytic vegetation, xerophytic scrub, dense forest.


Author(s):  
M.D. Wildsmith ◽  
I.C. Potter ◽  
F.J. Valesini ◽  
M.E. Platell

Benthic macroinvertebrates were sampled seasonally in the subtidal and upper and lower swash zones at two sites in each of six nearshore habitat types on the lower west coast of Australia. The habitat types, which differed mainly in the extent of their exposure to wave activity and whether sea grass and/or nearshore reefs were present, had been distinguished quantitatively using values for a suite of seven statistically-selected enduring environmental characteristics (Valesini et al., 2003). The core samples yielded 121 species representing eight phyla, among which the Polychaeta, Malacostraca and Bivalvia were the most speciose classes, contributing ∼38, 23 and 10%, respectively, to the total number of individuals. The total number of species and mean density of macroinvertebrates at the most protected habitat type (1), i.e. 70 and 209·2 individuals 0·1 m−2, respectively, were far greater than in any other habitat type. Habitat type influenced species composition to a greater extent than either zone or season. Furthermore, the extents of the differences among the species compositions of the six habitat types statistically matched the extents of the differences among the values for the suite of enduring environmental characteristics that distinguished each of those habitat types. Overall, the species composition at habitat type 1 was the most distinct, containing five abundant species of polychaetes that were adapted to deposit-feeding in calm waters with high levels of organic material and which were rare in all other habitat types. In contrast, the fauna at the most exposed habitat type was characterized by four crustacean species and a species of bivalve and polychaete, whose mobility and tough external surface facilitated their survival and feeding in turbulent waters. The zonal differences in faunal compositions among habitat types were greatest in the case of the subtidal zone. The faunal compositions differed among zones and seasons only at the most protected habitat type.


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