ECTOMYCORRHIZAL DIVERSITY ON BETULA-PAPYRIFERA AND PSEUDOTSUGA-MENZIESII SEEDLINGS GROWN IN THE GREENHOUSE OR OUTPLANTED IN SINGLE-SPECIES AND MIXED PLOTS IN SOUTHERN BRITISH-COLUMBIA
Md. Jones et al., ECTOMYCORRHIZAL DIVERSITY ON BETULA-PAPYRIFERA AND PSEUDOTSUGA-MENZIESII SEEDLINGS GROWN IN THE GREENHOUSE OR OUTPLANTED IN SINGLE-SPECIES AND MIXED PLOTS IN SOUTHERN BRITISH-COLUMBIA, Canadian journal of forest research, 27(11), 1997, pp. 1872-1889
The inoculum potential and diversity of the ectomycorrhizal fungal com
munity usually decrease on a site following logging. The objective of
this study was to determine if planting a mixture of tree species foll
owing logging retains a higher diversity of ectomycorrhizal fungi than
planting a single species. Paper birch (Betula papyrifera Marsh.) and
Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) were planted eithe
r alone or in mixture and in different proportions and densities on ea
ch of three sites in the southern interior of British Columbia. Ectomy
corrbizal types were characterized following detailed morphological ex
amination on 12 seedlings per plot at 4, 16, and 28 months following o
ut planting (field bioassay). Thelephora, E-strain, Rhizpogon (for Dou
glas-fir only), Mycelium radicis atrovirens, and Cenococcum mycorrhiza
e were the most abundant. The Thelephora mycorrhizae decreased in domi
nance over the sampling period from 82 to 41% of ectomycorrhizae on bi
rch and from 26 to 15% on Douglas-fir. Rhizopogon mycorrhizae remained
consistently abundant an Douglas-fir roots (36% of mycorrhizae at 4 m
onths to 37% at 28 months). By 28 mouths, 91% of birch and 56% of Doug
las-fir mycorrhizae were types common to the two species. This has imp
ortant implications for possible nutrient of carbon transfer between t
he two species. At 16 (P = 0.068) and 28 months (P = 0.088) following
outplanting, the evenness of the ectomycorrhizal community on Douglas-
fir root systems was higher in mixed than in single-species plots. Ric
hness (number of ectomycorrhizal types) and Simpson's diversity index
per seedling were not affected by tree mixture treatments. Planting de
nsity did not affect richness, evenness, or diversity. The ectomycorrh
izae that developed an Douglas-fir or birch seedlings grown in the gre
enhouse in soils from these sites were very similar to those that deve
loped in the field. This demonstrates that greenhouse bioassays can be
used to predict which types of ectomycorrbizae will form on seedlings
grown on disturbed sites, at least for the first few years following
outplanting.