Usha Srinivasan spent last summer exploring a part of the Yukon that is almost totally unknown. A PhD in mycology, the study of fungi, she has taken a close look at ecto-mycorrhizal fungi -- called ECM for short. These unique organisms are associated with the roots of most living plants, and Srinivasan's work has paid off with some new discoveries.

Srinivasan and several assistants collected ECM from several different sites around the Yukon. She wanted to study the ECM associated with tree roots growing under different conditions, so she sampled a burn site, a logged site that had been replanted and two sites with old growth trees.

Although she has not completed her lab work, she thinks that she has isolated between 30 and 40 different ECM, and so far she is only completely sure of the identity of one or two of them. Srinivasan thinks that as many as 90 percent of them have never been identified, so she will end up naming them herself, an exciting proposition for any scientist.

"I almost found it overwhelming when I realized that I had found new ones," she says.

ECM play a vital role in the living world as these fungi have a symbiotic relationship with the plants on which they live. The ECM provide essential minerals that may be hard for the plants to obtain on their own. In exchange the ECM receive carbon which they need to survive.

Some researchers have shown that ECM help replanted seedlings survive by protecting them against frost damage and some fungal diseases. But there is much that is not known about the species of ecto-mycorrhizal fungi that exist in North America, particularly in Western Canada.

Part of the problem is that telling one ECM from another is no easy task. ECM are identified in the laboratory, not out in the field, and the set of laboratory protocols runs four pages long. The work can be tedious and is always painstaking.

Some ECM produce mushrooms, but even identifying these fruiting bodies is not a major help for a mycologist as the field names for mushrooms may be slightly diff erent from the names of the ECM that produce them. To complicate matters even further, young ECM can look completely different from old ECM of the same genus.

To date there is no identification guide for ECM species documented in North America. The Pacific Forestry Center in Victoria is working on putting a guide together of the ECM species documented in Western Canada but for now mycologists like Srinivasan must rely on identification guides from Scandinavia and England, where ECM have been studied for a longer period of time.

Although Srinivasan has extensive experience as a research scientist, she has never worked on ECM in the boreal forest. She says that it is important to establish what ECM exist in the Yukon forests before any increase in logging possibly affects the range of species living here.

"It is possible to lose the ecto-mycorrihzal fungi in an area if there are constant clear cuts, especially of old growth forests, and they do not have the opportunity to recolonize either naturally or through replanting," she says.

Understanding the role that ECM play in northern forests can also help with efforts to establish sustainable forestry. Research has shown that seedlings regenerated naturally have a greater chance of surviving when replanted than seedlings grown in greenhouses, and ECM could have something to do with the success rate. They could provide the nutrients that make the difference in whether a replanted seedling survives.

Srinivasan points out that the seedlings replanted in the Yukon come from British Columbia, where they could be colonized by ECM completely different from the ones that live here. When the seedlings are replanted, they are colonized by Yukon ECM.

But sorting all of these relationships out will take time. "You would need to do this work for at least five years to get a good idea of what the diversity here is like and it can take even 20 years to truly understand the ecosystem of a forest, " she says.

For more information on this project, contact the Northern Research Institute at 668-8828.