Levia & Frost(2003)による『A review and evaluation of stemflow literature in the hydrologic and biogeochemical cycles of forested and agricultural ecosystems』(1p)から〕


 Stemflow is a spatially localized point input of precipitation and solutes at the plant stem and is of hydrological and ecological significance in forested and agricultural ecosystems. The purpose of this review is to: (1) critically evaluate our current understanding of stemflow; (2) identify gaps in our present knowledge of stemflow; and (3) stimulate further research in areas where present knowledge is weak. The review begins by analyzing stemflow drainage and nutrient inputs under diverse vegetal cover. Stemflow inputs are then examined as a function of meteorological conditions, seasonality, interspecific and intraspecific differences among and within species, canopy structure, spatiality, and atmospheric pollutanta in urban environments. Stemflow modeling studies are also reviewed and evaluated. Stemflow yield and chemistry are the result of the interaction of the many complex variables listed. By analyzing each separately, it may be possible to isolate their individual affects on stemflow production and chemistry. A comprehensive understanding of each influencing factor would enable the accurate modeling of stemflow water and nutrient inputs into agricultural and forest soils which may result in the optimization of timber and crop harvests.
 Some areas where present knowledge is particularly weak are: (1) stemflow production and nutrient transfers in northern boreal forests (aspen, birch, conifers) and desert cacti; (2) chemical enrichment of stemflow from live trees charred by forest fires; (3) stemflow yield and nutrient inputs during the winter season; (4) intraspecific variation in stemflow production and chemistry; (5) stemflow chemistry from standing dead trees; (6) influence of canopy structure on stemflow chemistry; (7) understory stemflow generation and nutrient transfer; and (8) stemflow enrichment associated with insect infestations.

Keywords: Stemflow; Forest hydrology; Agricultural hydrology; Nutrient cycling; Canopy structure』


1. Introduction
2. Stemflow measurement methods
 2.1. Measuring stemflow production and chemistry
 2.2. Interpreting stemflow studies
3. Stemflow hydrology and chemistry in different ecoregions
 3.1. Ecoregion and stemflow generation
 3.2. Ecoregion and stemflow chemistry
 3.3. Evaluation
4. Influence of meteorological conditions on stemlflow generation and chemistry
 4.1. Meterological conditions and stemflow yield
 4.2. Meterological conditions and stemflow chemistry
 4.3. Evaluation
5. Seasonality
 5.1. Stemflow yield and seasonality
 5.2. Seasonality and the chemical enrichment of stemflow
 5.3. Evaluation
6. Interspecific and intraspecific variation in stemflow hydrology and chemistry
 6.1. Interspecific stemflow generation
 6.2. Intraspecific stemflow generation
 6.3. Interspecific variation in stemflow chemistry
 6.4. Evaluation
7. Canopy structure
 7.1. Canopy structure and stemflow production
 7.2. Canopy structure and stemflow chemical enrichment
 7.3. Evaluation
8. Spariality of stemflow inputs
 8.1. Spatial variability of stemflow inputs
 8.2. Spatial variability of stemflow chemical inputs
 8.3. Spatial variability of stemflow inputs and geomorphological processes
 8.4. Evaluation
9. Pollutants and stemflow in forest nutrient cycles
 9.1. Stemflow chemistry and pollutants
 9.2. Stemflow and acidic deposition
 9.3. Evaluation
10. Stemflow modeling
 10.1. Stemflow modeling studies
 10.2. Evaluation
11. Conclusion

Table 1 Range of selected stemflow production values under diverse vegetation cover in tropical, temperate, semi-arid and atid ecorigions(熱帯、温帯、半乾燥帯、乾燥帯地域における異なる植生の樹幹流量についての代表的な値)
Vegetation type
Stemflow(% of incident precipitation)
Tropical montane rainforest 13.6 Herwitz(1986a)
Tropical rainforest 1.8 Lloyd and de Marques(1988)
Cacao plantation 1.99 Opakunle(1989)
Tropical dry forest 0.6-0.9 Kellman and Roulet(1990)
Tropical montane rainforest <1.0 Veneklaas and Van Ek(1990)
Tropical rainforest 0.9-1.5 Marin et al.(2000)
Pine-hemlock-beech plots 1.2-9.6 Voigt(1960)
Pinus radiata plantation 3.1-3.9 Crockford and Khanna(1997)
Dry sclerophyll forest 4.8 Crockford and Richardson(1990b)
Subalpine balsam fir forest 3.0-8.0 Olson et al.(1981)
Northern red oak plantation 4.0 Durocher(1990)
Pinus radiata plantation 11.2 Crockford and Richardson(1990b)
Evergreen-broadleaf forest 14.0-20.0 Masukata et al.(1990)
Slash pine forest 0.94-10.4 Tang(1996)
Japanese pine forest 6.6-15.7 Taniguchi et al.(1996)
Chihuahuan desert shrubs 4.0-45.0 Mauchamp and Janeau(1993)
Semi-arid shrubs 0.76-5.14 Navar〔最初のaの頭に´〕(1993)
Chihuahuan desert shrubs 2.0-27.0 Martinez-Meza and Whitford(1996)
Cresotebushes 5.9-26.9 Whitford et al.(1997)
Thornscrub community 3.0 Navar〔最初のaの頭に´〕 et al.(1999)
Laurel forest 1.2-13.6 Aboal et al.(1999)
Mediterranean holm oak forest 2.6-12.1 Bellot et al.(1999)

Table 2 Range of selected stemflow enrichment values of K+ and Mg2+ in tropical, temperate, and Mediterranean ecoregions(熱帯、温帯、地中海地域における樹幹流のK+とMg2+の代表値 )
Vegetation type
Stemflow 樹幹流 Reference


Tropical rainforest 1.5-2.8 0.2-0.3 Jordan(1978)
Subtropical eucalypt forest 0.9 1.1 Westman(1978)
Tropical lowland dipterocarp 0.66 0.18 Radzi Abas et al.(1992)
Sessile oak forest 1.48 0.58 Carlisle et al.(1967)
Aspen-black spruce forest 0.01-2.8 0.006-0.5 Verry and Timmons(1977)
Sugar maple-yellow birch 0.8-1.25 0.04-0.05 Foster and Nicholson(1988)
Northern hardwood forest 0.9 0.06 Likens and Bormann(1995)a
Mediterranean holm oak forest 0.3-2.2 0.02-0.2 Bellot and Escarre(1991)
Mediterranean holm oak forest 0.5-2.6 0.06-0.3 Bellot et al.(1999)
a Stemflow nutrient input assumed to be 3% of total throughfall and stemflow nutrient flux (Ragsdale et al., 1992).

Table 3 Acidic deposition and mean pH of incident bulk precipitation and stemflow(直接の降水および樹幹流についての酸性沈着物とpHの関係)
pH Reference
Bulk precipitation
Southeastern Australiaa Pinus radiata 5.30 4.24 Crockford et al.(1996a,b)
Northern Australiaa Ceratopelatum virchowii 5.42 4.48 Herwitz(1991)
Northeastern Mexicoa Quercus spp. 6.59 6.06 Silva and Rodriguez(2001)
Central Nova Scotiab Acer saccharum 4.3 5.7 Freedman and Prager(1986)
Central Bohemiab Fagus sylvatica 4.15 4.00 Skrivan〔rの頭にv〕 et al.(1995)
Western Japanb Ilex rotunda 5.2 5.7 Takagi et al.(1997)
Southeastern Chinab Cunninghamia lanceolata 6.31 4.14 HouBao et al.(1999)
Northern Bavariab Fagus sylvatica 4.65 4.60 Chang and Matzner(2000)
a Site not exposed to significant acidic deposition.
b Site exposed to significant acidic deposition.