• Journal of Korean Society of Forest Science
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• v.84 no.3
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• pp.394-405
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• 1995

Certain ericaceous understory plants of temperate forests proliferate following forest clearcutting and fire. Rapid vegetative growth of these plants may affect conifer regeneration due to their strong competitive abilities and allelopathic properties. Planted conifers in these shrub-dominated habitats experience "growth check" which may result in a loss of productivity or in extreme cases total failure of forest regeneration. This growth check phenomenon is exemplified in Calluna Sitca spruce Scots pine ecosystems of western Europe, Kalmia black spruce ecosystem of eastern Canada and Gaultheria-cedar/hemlock ecosystem of the Pacific Northwest of the United States. Dynamics of Kalmia black spruce ecosystem following disturbance was used to explain the mechanism of conifer growth inhibition and their regeneration failure. It is argued that in addition to competition for nutrients, Kalmia allelopathy plays a major role in growth inhibition of black spruce. This conclusion is supported by the results of various field, laboratory and greenhouse experiments. Eight phenolic compounds were isolated and identified from the leaves of Kalmia angustifolia, four of which are known to be highly phyotoxic to black spruce. Methods of overcoming the allelopathic effects of Kalmia in order to enhance black spruce regeneration in Kalmia-dominated sites are discussed.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2019.08a
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• pp.192-192
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• 2019

• Journal of Korean Society of Forest Science
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• v.87 no.3
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• pp.429-444
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• 1998

Objective of this study was to select ectomycorrhizal fungi for black spruce(Picea mariana) inoculation to overcome the growth inhibitory effects of Kalmia angustifolia. Nineteen isolates representing 11 species of ectomycorrhizal fungi were tested for their abilities to grow and form mycorrhizae with black spruce seedlings in the presence of water leachate of leaves of Kalmia. Mycelium growth of 9 isolates were inhibited by the leaf leachate. Colony diameter and biomass of the other 10 isolates were either increased or unaffected under the same conditions. Acidic pH of the culture medium(pH 3 and 4) inhibited some of the fungi, but a combination of acidic pH and the leaf leachate was more inhibitory. Thirteen isolates were able to form ectomycorrhizae with black spruce in presence of 25% leaf leachate in pure culture. Four isolates, Paxillus involutus(NF4), Cenococcum geophilum(GB12), Laccaria laccata(GB23), and E-strain(GB45) formed mycorrhizae more successfully than the others in presence of up to 50% Kalmia leaf leachate. Black spruce seedlings pre-inoculated with these fungi were grown with Kalmia leaf leachate and live Kalmia plants during a four month greenhouse experiment. Abundant mycorrhizae(77-91% of root tips) were developed on seedlings pre-inoculated with P. involutus, L. laccata and E-strain but relatively poor mycorrhization(32% of root tips) resulted with C. geophidum. Over 90% of the short root mycorrhizae were attributed to the inoculated fungi although indigenous mycorrhizae also occurred on most seedlings. Persistence of the mycorrhizae was not affected by living Kalmia plants. Over 80% of the mycorrhizae on seedlings inoculated with P. involutus, L. laccata and E-strain and 53% of the mycorrhizae on seedlings inoculated with C. geophilum were attributable to the inoculant fungi. Control seedlings formed about 45% ectomycorrhizal short roots with indigenous fungi. The L. laccata and C. geophilum inoculated seedlings exhibited enhanced mycorrhizae formation in presence of Kalmia leaf leachate. Mycorrhizae formation with inoculant fungi was 4-15% lower at pH 4 than at pH 5, with the greatest inhibition occurring for L. laccata. Seedlings inoculated with P. involutus had the greatest shoot and root growth followed by L. laccata and E-strain inoculated seedlings. The P. involutus and L. laccata inoculated seedlings were significantly taller with more shoot dry biomass than the uninoculated(control) seedlings. E-strain inoculated seedlings had significantly higher shoot dry biomass and significantly lower number of first order lateral roots compared to the control but other growth parameters such as height, root dry weight and number of short root tips were not significantly different from the control. Seedlings inoculated with C. geophilum were not significantly different from the uninoculated seedlings in any of the growth parameters except for the number of first artier lateral roots which was significantly less than the control seedlings.