Coniferous Forests

ZONE DESERT DESERT FOREST CONIFEROUS DECIDUOUS... 

Coniferous forest Coniferous forest Cj Mixed forest... 

Measurement of dry deposition is more complicated, not only because dry deposition varies with the type of land cover (e.g., bare soil, grass, deciduous forest, coniferous forest) but also because deposited chemicals are more difficult to collect from these complex surfaces for analysis. The dry bucket of Fig. 4.37, originally intended to collect dry deposition, is not a very close approximation to natural surfaces, and therefore yields results of imcertain meaning. 

As with other factors, no direct statements can be made relating the reaction of a soil to its corrosive properties. Extremely acid soils (pH 4 0 and lower) can cause rapid corrosion of bare metals of most types. This degree of acidity is not common, being limited to certain-bog soils and soils made acid by large accumulations of acidic plant materials such as needles in a coniferous forest. Most soils range from pH5 0 to pH8 0, and corrosion rates are apt to depend on many other environmental factors rather than soil reaction per se. The 45-year study of underground corrosion conducted by the United States Bureau of Standards included study of the effect of soils of varying pH on different metals, and extensive data were reported. 

Although seen only occasional during the first half of this century, winter injury of first-year red spruce needles has become an annual event in the coniferous montane forest area, resulting in the formation of red-brown first year needles that subsequently desiccate and are shed 20, 21). The loss of foliage reduces photosynthesis and the obligatory accumulation of carbohydrate in the twigs and root systems. There is some evidence that this phenomenon involves both natural and anthropogenic causal factors. 

Figure 5. Photographs of Camels Hump Mountain montane coniferous zone taken in (a) 1963 and (b) 1983 showing changes in forest composition.

Negligible quantities of wood may be removed when tropical forests are cut for shifting cultivation or pasture conversion. In contrast to the temperate coniferous forests of the Northwest USA, only small quantities of wood are usually exported as a result of timber operations in tropical evergreen forests. In... 

Temperate Coniferous Forest Coastal redwood USA Primary 1150-3200 28... 

Boreal Coniferous Forest Global Average Primary 165 89... 

Figure 6. An undisturbed primary temperate coniferous forest in the Pacific Northwest, USA (Olympic National Park). The nutrient balance of this forest is in a relative equilibrium with elemental inputs closely approximating elemental losses.

Figure 7. Another temperate coniferous forest site of the Pacific Northwest, USA following clearcutting and slash burning. Severe levels of deforestation result in large quantities of nutrient losses through wood export, biomass burning and accelerated erosion and leaching losses. (Photograph is by courtesy of Dian L. Cummings. ...

Fig. 8-4 Typical soil horizon sequence for a Spodosol developed under a coniferous forest (left) and a Mollisol developed under grasses and herbaceous plants.

Plate 3 shows a map of dominant soil orders for the entire world. Although this map necessarily lacks detail due to its scale, the relationship between soils and the biosphere is evident. Different terrestrial ecosystems are correlated with climatic conditions and different soils are correlated with both. For example, Mollisols are common in areas where there are prairies or steppes a result of grasses as the dominant vegetation and low, seasonal rainfall. Spodosols occur where coniferous forests dominate and the climate is cold and wet. Comparing Fig. 8-5 and Plate 3 carefully will show how strong this correlation is for the entire Earth. 

Davidson, E.A., Hart, S.C. and Firestone, M.K. 1992 Internal cycling of nitrate in soils ofamature coniferous forest. Ecology 73 1148-1156. 

Munthe J, Hultberg H, Iverfeldt A. 1995b. Mechanisms of deposition of mercury and methyl-mercury to coniferous forests. Water Air Soil Pollut 80 363-371. 

P. T. Rygiewicz, C. S. Blodsoe, and R. J. Zasoski, Effects of niycorrhizae and solution pH on C N) ammonium uptake by coniferous. seedlings, Canadian Journal Forest Research 74 885 (1984). 

R. Fogel, Root turnover and productivity of coniferous forests, Plant Soil 71 75 (1983). 

McEnroe, N.A. and Helmisaari, H.S., Decomposition of coniferous forest litter along a heavy metal pollution gradient, south-west Finland, Environ Pollut, 113 (1), 11-18, 2001. 

SL 1.1 662 NE42.50 30° Coniferous broad-leaved mixed forest (natural forest), consists mainly of Engelhardtia chrysolepis Hance, Bridelia monoica (Lour.) Merr., and Machilus velutina Champ. July 1998... 

WKS 1.6 315 NE50° 22° Coniferous broad-leaved mixed forest (natural May 1996... 

Pennanen T (2001) Microbial communities in boreal coniferous forest humus exposed to heavy metals and changes in soil pH a summary of the use of phospholipids fatty acids, Biolog and H-thymidine incorporation methods in field studies. Geoderma 100 91-126... 

Among the natural areas in the Ebro River basin, a broad spectrum of landscapes is scattered, ranging from boreal-alpine coniferous forests, mixed deciduous forests, Mediterranean evergreen and mixed forest and shrubs, and semi-arid treeless formations. 

Kristensen HL, Gundersen P, Callesen I, Reinds GJ (2004) Throughfall nitrogen deposition has different impacts on soil solution nitrate concentration in European coniferous and deciduous forests. Ecosystems 7 180-192... 

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