Effect of Urban Environmental Stress on Tree Vitality and ectomycorrhiza of Roadside Tilia sp.

Urban trees face numerous stress factors including de-icing salt in order to provide ecosystem services to cities. Mycorrhiza can mitigate environmental stresses but their role in mitigating urban specific stresses is not well known. We examined the effects soil chemistry on Tilia sp. planted along streets and it´s associated ectomycorrhiza. We compared park trees, trees from side streets, and trees from main streets with different salt stress levels . We show that 1) Tree vitality as well as ectomycorrhizal colonization decreases with increasing additions and sodium levels, 2) Tree vitality and colonisation as well at morphotype diversity were positively correlated to soil Mg. External mycelia production, measured with ingrowth bags was on the other hand higher in street trees than in parks and was not negatively correlated with Na but showed on the other hand a negative correlation to dissolved N. An explanation to the opposite patterns of colonization rate and production could be that the stressed environment causes high belowground turnover of roots and mycelia.