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Current projects

Kirsten D. Hannam, Gerry H. Neilsen, Tom Forge, Denise Neilsen, Istvan Losso, Melanie D. Jones, Craig Nichol, Mesfin M. Fentabil. Irrigation practices, nitrogen amendments and mulches affect nutrient dynamics in a young Merlot (Vitis vinifera L.) vineyard. Canadian J Soil Science, accepted.

Water conservation practices for production of woody perennial horticultural crops: beneficial management practices for mitigating greenhouse gas emissions


Adaptation to increased demand for food under changing climates will likely require more irrigated production; however, water for irrigation is limited. Consequently, conservative management practices to improve the efficiency of agricultural water use are being adopted. Frequently missing from studies of ecosystem responses to irrigation are the effects on greenhouse gas (GHG) emissions and soil organic matter. Irrigation of dry soils is likely to result in an increase in CO2 emissions from soils; however, irrigation also increases plant growth and carbon inputs into the soil, so the net effect on the systems carbon balance is unknown.  The overall objective of the project is to determine how water conserving management practices (different rates of irrigation; organic amendments) affect GHG emissions and carbon sequestration in fruit production systems in the semi-arid Okanagan Valley. Kirsten Hannam and Val Ward, in collaboration with colleagues from Agriculture and Agrifood Canada, Landcare Research New Zealand, and the James Hutton Institute of Scotland, are using isotopic signatures of CO2 emissions from soil to study the effects of grape pumice compost, wood and bark mulch, and different methods of irrigation on the source of carbon released from soil. Preliminary evidence suggests that carbon in the irrigation water can contribute to CO2 efflux from these soils. By increasing understanding of the processes underlying effects of irrigation on GHG emissions we can apply the results to agricultural systems in other parts of Canada and other semi-arid regions. 

Involvement of ecto- and ericoid mycorrhizal fungi in soil organic matter breakdown and saprotrophy


Peatlands and northern temperate forest soils are major repositories of soil carbon.  A portion of this carbon is released through respiration of soil microbes.  Whether this loss is balanced by fresh inputs of photosynthetically-fixed carbon into the soil through leaf litter, root exudation and death, and allocation to mycorrhizal fungi depends on many factors: climate, stage of forest development, frequency of wildfire, and whether the forest is dominated by ectomycorrhizal or arbuscular mycorrhizal trees. Because climate change will be accelerated if there is a net release of carbon from soils, we are studying the role of various types of mycorrhizal fungi in the soil carbon cycle.  In particular, we are interested in determining the extent to which ericoid and ectomycorrhizal fungi use soil carbon to meet their carbon demands.  At this point, Erin Feldman, Annick Sevigny, and Josh Smith, together with collaborators in France, Italy and New Zealand, are studying gene expression and carbon assimilation in Oidiodendron maius/Vaccinium systems in the lab to address this question.  Earlier, Lori Phillips found that ectomycorrhizal fungi appear to contribute as much extracellular enzyme activity to soil organic matter breakdown as saprotrophic fungi do.

Phillips LA, Ward V, Jones MD. 2014. Ectomycorrhizal fungi contribute to soil organic matter cycling in sub-boreal forests. ISME Journal 8:699-713.


Expanding cherry production in British Columbia under climate change: potential for mulch and compost to improve biological buffering of soils against pathogens


Cherries are a high-value crop produced in the Okanagan Valley of British Columbia. Recent models have indicated that areas suitable for cherry production have expanded northward and up in elevation, however increased production could put increased pressure on water resources. As fewer options are now available for soil pathogen control, new orchards provide a unique opportunity to test methods for retaining and encouraging beneficial soil microbes in these new soils. Under a project headed by Dr. Louise Nelson, and in consultation with PARC scientists and Okanagan cherry growers, Paige Munro, Kirsten Hannam, and Tanja Vogel will study and demonstrate orchard management practices for optimizing both water use and soil biological resilience in new orchards. Using sweet cherry as a key indicator crop, we will assess the impact and cost effectiveness of soil amendments (mulch, compost) and selected irrigation methods (including deficit irrigation) on water use efficiency, soil water holding capacity, crop production and soil health in two newly planted north Okanagan orchards and one well-established central Okanagan orchard.

Recent or completed projects

Matthew Whiteside

Whiteside DM, Durall DM, Jones MD. 2014. Ectomycorrhizal fungi transfer organic phosphorus to plants within a common mycorrhizal network based on plant host inorganic phosphorus availability. Ecological Society of America annual meeting, Sacremento CA.

Influence of plant nutrient status and carbon supply on the distribution of N and P by an ectomycorrhizal fungus in a common mycelial network.

In nature, ectomycorrhizal (ECM) fungi can be found in common mycorrhizal networks (CMNs) consisting of two or more plant individuals connected by a shared mycorrhizal fungus. However, the mechanisms that control preferential nutrient transfer from ECM fungi to each individual plant host are not well understood. We hypothesized that plant nutrient status might drive this process because it can influence photosynthate supplied to the fungus. Matt Whiteside assempled Petri plates consisting of two lodgepole pine seedlings in a CMN with Suillus tomentosus on P-depleted media lacking C. Following CMN formation, the foliage of each seedling was treated with either a P solution or sterile water. After 3 d, a solution of either inorganic P (sodium 32P phosphate), or organic P (serine 32P phosphate), was injected into a well that only hyphae could access. When organic P was supplied to the hyphal well, less 32P was translocated to the shoots of the P-enriched hosts. By contrast, when hyphae were supplied with inorganic P, there was no significant 32P translocation to the shoots of P-enriched versus water-control plants. These results suggest that preferential allocation of P to host plants by their associated mycorrhizal fungi is likely driven by substrate type and host nutrition status.

Ectomycorrhizal fungal communities in subalpine clearcuts - do they differ physiologically from those on seedlings in mature forests?

Different ectomycorrhizal fungi (EMF) colonize seedlings in forests and clearcuts. We have been testing the hypothesis that soil abiotic properties interact with EMF physiologies to determine which fungi are successful colonizers. As predicted by our hypothesis, Jennifer Walker found differences in EMF communities between clearcuts and subalpine forests that were associated with differences in mycorrhizoplane enzyme activities. By contrast, and in contradiction to our hypothesis, neither EMF communities nor their enzyme activities varied with substrate type (decayed wood vs mineral soil), even though soil chemical properties differed substantially. This suggests that the difference in enzyme profiles between forest and clearcut communities was associated with species differences, rather than representing functional attributes that adapted fungi to specific edaphic environments. To test this idea, Bailey Nicholson reciprocally transplanted 1-yr-old, naturally-colonized subalpine fir seedlings between and within clearcuts and adjacent forests. She detected a high degree of phenotypic plasticity for enzyme activity in both forest and clearcut EMF communities.  Moreover, seedlings did not grow larger or acquire more nutrients when colonized by EMF from the ‘home’ environment. These results suggest that fungal attributes other than enzyme-mediated nutrient acquisition, perhaps dispersal and persistence strategies, determine the relative success of specific EMF in colonizing seedlings in clearcuts.

Walker JKM, Phillips LA, Jones MD. 2014. Ectomycorrhizal fungal hyphae communities vary more along a pH and nitrogen gradient than between decayed wood and mineral soil microsites. Botany doi 10.1139/cjb-2013-0239. Invited paper for special issue on Advances in Tree Biology.

Walker JKM, Jones MD. 2013. Little evidence of niche partitioning among ectomycorrhizal fungi on spruce seedlings in decayed wood versus mineral soil microsites. Oecologia 173: 1499-1511. doi 10.1007/s00442-013-2713-9

Jones MD, Twieg BD, Ward V, Barker J, Durall DM, Simard SW. 2010. Functional complementarity of Douglas-fir ectomycorrhizas for extracellular enzyme activity after wildfire or clearcut logging. Functional Ecology 24: 1139–1151

Jones MD, Durall DM, Cairney JWG. 2003. Tansley review: Ectomycorrhizal fungal communities in young stands regenerating after clearcut logging. New Phytol. 157: 399-422.


Millimeter-scale soil processes and associated soil fungal communities


Soil is a very heterogeneous environment, with variations in aeration, moisture and chemical properties at very fine scales.  Denise Brooks, Aaron Godin and Kiran Lidher used a soil imprinting technique to localize phosphomonoesterase activities and then to study the mm-scale chemical and biological properties of these enzyme hot spots.  Aaron and Kiran established that phosphatase activities were positively related to soil C and N at these fine scales. Denise and Aaron found that, in approximately half of the hotspots, saprotrophic fungi outnumbered ectomycorrhizal fungi.  In the other half, the two types of fungi were equally represented. Although ectomycorrhizal roots can release extracellular phosphatase into the soil, it appears that, at some soil microsites with high N and C, saprotrophic fungi outcompete ectomycorrhizal fungi.

Godin AM, Lidher KK, Whiteside MD, Jones MD. 2015. Control of soil phosphatase activities at millimeter scales in a mixed paper birch - Douglas-fir forest: the importance of carbon and nitrogen. Soil Biol Biochem. DOI: 10.1016/j.soilbio.2014.09.022

Brooks D, Twieg BD, Grayston SJ, Jones MD. 2013. Physical extent, frequency, and intensity of phosphatase activity varies on soil profiles across a Douglas-fir chronosequence. Soil Biol Biochem 64: 1-8.

Dong S, Brooks D, Jones MD, Grayston SJ. 2007. A method for linking in situ activities of hydrolytic enzymes to associated organisms in forest soils. Soil Biol. Biochem. 39: 2414-2419

Forest management and ectomycorrhizal fungi

We have taken part in a number of interdisciplinary studies that examined how ectomycorrhizal fungal (EMF) communities are influenced by specific silvicultural practices. In general, we have found that, although diversity does not necessarily drop, EMF communities on seedlings in clearcuts differ substantially from those in forests. Fertilization to maintain balanced foliar nutrient levels does not have a major effect on EMF communities.  


In the subalpine forests of the Engelmann Spruce - Subalpine Fir biogeoclimatic zone of British Columbia, the number of mycorrhizal morphotypes decreased dramatically by 18 months after winter logging. When young non-mycorrhizal spruce seedlings were used as bait, mycorrhizal colonization and the diversity of morphotypes was 50 % higher in the periphery of clearcuts (2-3 m from the forest edge) than it was at 16 m or greater from the forest edge. Except at the periphery, colonization and ECM fungal diversity were not different between seedlings planted in the clearcut and in the forest. Interestingly, when commercially produced spruce seedlings were planted on mounds at the same site, no difference in colonization or morphotype diversity were apparent with increasing distance from the forest edge. These studies were part of the Sicamous Creek Silviculture Systems Trial established by the BC Ministry of Forests, Kamloops Region. We found a similar pattern, although less distinct in the Interior Cedar Hemlock zone in central BC (Durall et al. 1999). More dramatically, the diversity of ectomycorrhizal root tips decreased by 5 m away from dispersed retention patches of green trees on Vancouver Island, even one year after harvest. In other studies we found transient, minor negative effects on EMF communities of using mechanical rather than chemical treatment for suppressing competition from herbaceous plants and of planting seedlings in monocultures rather than in mixtures. Leaving coarse woody debris behind after logging had a small, but detectable effect on the EMF communities on 12-year-old spruce saplings.  Interestingly, a greater diversity of EMF colonized Douglas-fir seedlings in unscreefed clear-cuts than in recent wildfire sites.

Hay TN, Phillips LA, Nicholson BA, Jones MD. 2015. Ectomycorrhizal community structure and function in interior spruce forests of British Columbia under long term fertilization. Forest Ecology & Management 350: 87-95

Barker J, Simard SW, Jones MD, Durall DM. 2013. Ectomycorrhizal fungal community assembly on regenerating Douglas-fir after wildfire and clearcut harvesting. Oecologia 172: 1179-1189.

Walker JKM, Ward V, Paterson C, Jones MD. 2012. Coarse woody debris retention in subalpine clearcuts affects ectomycorrhizal root tips community structure within fifteen years of harvest. Applied Soil Ecology 60:5-15

Jones MD, Phillips LA, Treu R, Ward V, Berch S. 2012. Functional responses of ectomycorrhizal fungal communities to long-term fertilization of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) stands in central British Columbia. Applied Soil Ecology 60: 29-40.

Douglas-fir seedlings. Plant Ecology & Diversity 3: 221-233; DOI: 10.1080/17550874.2010.502564

Jones MD, Twieg BD, Ward V, Barker J, Durall DM, Simard SW. 2010. Functional complementarity of Douglas-fir ectomycorrhizas for extracellular enzyme activity after wildfire or clearcut logging. Functional Ecology 24: 1139–1151

ectomycorrhizas: a quantitative assessment using meta-analysis. Ecology 89: 1032-1042.

Jones MD, Twieg BD, Durall DM, Berch SM. 2008. Location relative to a retention patch affects the ECM fungal community more than patch size in the first season after timber harvesting on Vancouver Island, British Columbia. For. Ecol. Manage. 255: 1342-1352.

Simard SW, Jones, M.D., Durall, D.M., Hope, G.D., Stathers, R.J., Sorensen, N.S., and Zimonick, B.J.  2003.  Chemical and mechanical site preparation: effects on Pinus contorta growth, physiology, and microsite quality on steep forest sites in British Columbia.  Can. J. For. Res. 33: 1495-1515.

Jones MD, Durall DM, Cairney JWG. 2003. Tansley review: Ectomycorrhizal fungal communities in young stands regenerating after clearcut logging. New Phytol. 157: 399-422.

Jones MD, Hagerman SH, Gillespie M. 2002. Ectomycorrhizal colonization and richness of previously colonized, containerized Picea engelmannii does not vary across clearcuts when planted in mechanically site-prepared mounds. Can. J. For. Res.32: 1425-1433.

Hagerman SM, Jones MD, Bradfield GE, Gillespie M, Sakakibara, S.  1999.  Ectomycorrhizal colonization of Picea engelmannii x glauca seedlings planted across cut-blocks of different sizes.  Can. J. For. Res. 29: 1856-1870

Durall DM, Jones MD, Wright E, Kroeger P, Coates KD.  1999. Species richness of ectomycorrhizal fungi in cutblocks of different sizes in the Interior Cedar-Hemlock forests of northwestern British Columbia: sporocarps and ectomycorrhizae.  Can. J. For. Res. 29: 1322-1332.

Hagerman SM, Jones MD, Bradfield GE, Gillespie M, Durall DM.  1999. Effects of clear-cut logging on the diversity and persistence of ectomycorrhizae at a subalpine forest.  Can. J. For. Res. 29: 124-134.Jones MD, Durall DM, Harniman SMK, Classen DC, Simard SW.  1997. Ectomycorrhizal diversity of Betula papyrifera and Pseudotsuga menziesii seedlings grown in the greenhouse or in single-species and mixed plots in southern British Columbia. Can. J. For. Res. 27:1872-1889

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