March 2000 - Forest Regeneration

For decades, trembling aspen was considered a weed. Canadian forest companies have spent millions of dollars on herbicide spraying forest_regeneration1.jpg (8492 bytes)

programs to eradicate aspen from their conifer plantations. In the process, they may have unwittingly been killing the nurse that was protecting their babies. With the advent over the past 15 years of massive pulp projects like the Alberta Pacific Forest Industries Inc (AlPac) plant and a boom in the construction of oriented strand board facilities, the issue of mixed wood management has gained national attention in the industry. In a new development in the mixed wood area, researchers working with AlPac are proposing a system of natural regeneration that could radically change how the users of spruce from Canada's expansive fire origin boreal forest harvest and regenerate their spruce resources. It also offers what scientists believe is an economically viable alternative to clear cutting. "I think we should plant spruce in aspen cutblocks and let spruce cuts grow back to aspen," says Dr. Gitte Grover, AlPac's forest ecology research program manager. She and many other academic colleagues some working with the National Centre for Forestry Excellence in Edmonton believe that if Canadian forest companies are serious about managing the ecosystem so that the fire origin boreal forest is maintained as closely as possible in its natural state, then the importance of aspen to the regeneration of spruce cannot be taken lightly. Ignoring this natural succession will eventually lead to excessive mining of soil nutrients and will have a serious negative impact on indigenous wildlife species. "Replanting spruce after cutting spruce goes totally against natural succession," says Grover, noting that in a natural situation spruce burns and aspen comes back. "I'm sure that there are big implications for soils, for your humus composition, and for your nutrient cycling. In nature, it alternates, but in the forest industry we stick to single species management." What researchers have discovered is that aspen is a nurse species. It protects immature spruce in the understory from late spring frosts, hail and drought. It reduces competition, especially from tall grasses, and studies indicate that aspen in a mixed wood stand reduces the incidence of terminal weevil and spruce budworm.

Aspen also shares nutrients with spruce because its leaves rot faster and provide the forest floor with additional potassium. Aspen roots also explore different areas of the forest floor. "To see that aspen could actually be beneficial means you have to change your way of thinking," says Grover. What she and other deciduous consuming companies in Alberta are proposing is a new approach to regenerating the boreal forest, as well as a new government yardstick to measure successful regeneration. At present, companies are required to replace harvested spruce with spruce seedlings. They must achieve certain growth rates within specified time frames.

Key to New Approach is Monitoring

There is little doubt that aspen has nursing properties insofar as its relationship with spruce understory is concerned, but left unchecked the "nurse" tends to turn psychotic and smother its spruce charges, according to representatives from the coniferous side of the forest industry. Never underestimate the regenerative power of aspen, say staff at Alberta's Vanderwell Contractors Ltd, the coniferous representative in a partnership pioneering a new approach to harvesting and assisting natural regeneration of mixed wood stands in the fire origin boreal forest. Vanderwell Contractors owns a sawmill in Slave Lake, Alberta, with 40 per cent of its conifer supply within Alberta Pacific Forest Industries Inc.'s (AlPac) 60,000 square kilometre Forest Management Area (FMA).

AlPac intends to use a new harvesting and reforestation method that depends heavily upon natural succession, where aspen is allowed to regenerate in conifer stands because of its scientifically proven benefits to conifer regeneration. While he agrees with staff at AlPac that this new approach to harvesting and assisting natural regeneration of mixed wood stands in boreal forest is an alternative to clear cutting, Vanderwell Contractors operations forester Darren Platt says close monitoring of stand regeneration is vital. He adds that as far as Vanderwell Contractors is concerned, it cannot depend solely on natural regeneration of spruce, even if 20 to 40 seed trees per hectare are left to induce natural regeneration. "If you don't give conifers a helping hand, all you are going to grow back is aspen," he says.

Without intervention, he says it would take nature 200 years to accomplish the type of growth that is required by the conifer branch of the forest industry. "The whole industry would collapse if we allowed that," he says. While they strongly support the natural succession approach to managing the boreal forest, where aspen is allowed to grow more freely on conifer dominant stands, AlPac staff agree with Platt that the "helping hand" approach is also important. "The beauty of mixed wood management is that you don't have to be afraid of failure," says AlPac forest ecology research program manager Dr. Gitte Glover, "because you have so many options and possibilities. You are not constrained." This fall, the partners will begin using this new harvesting and regeneration approach on one forest management unit. Platt says while the new regenerative approach may require much less planting of spruce seedlings per hectare, the key is to maintain a balance. What this new approach will require, he says, is a lot more "rubber boot time." This is time spent monitoring the regenerative process at various stages much more than what is being done now on traditional reforested stands in order to meet government requirements. Regular monitoring may result in prescriptive measures such as planting older spruce seedlings to improve stem count, commercial thinning and fertilization. Vanderwell Contractors has also not ruled out herbicide spraying of aspen as one way to maintain the aspen/spruce balance.

What aspen users are proposing is that, in addition to intensive forest management on a block by block basis to ensure a sustainable wood resource, the government permit land base management and natural regeneration in mixed wood areas with the main objectives being overall ecosystem management and maintenance of biodiversity. The Alberta government has assigned a task force to study this approach in detail and Grover hopes that companies harvesting wood in the province's mixed wood stands will be given this new option. Successful implementation in Alberta could put other provinces in the hot seat as to how well they are managing their boreal forests. The main concern of sawmills, which are the primary consumers of spruce, is whether this system will maintain their wood basket. Grover believes it will and has proposed two harvesting methods-a one pass or a two pass system. The companies' first need is to have a clear understanding of their wood inventory. Next, they need to target mixed wood stands consisting of mature aspen and understory spruce numbering at least 400 stems per hectare and about 40 years old. Using the two pass system, the feller buncher is sent into the cutblock using an eight metre wide corridor and harvesting aspen by reaching eight metres to either side, placing the stems in the corridor. To protect against windthrow, the operator leaves 24 metres of untouched spruce and aspen between each corridor.

Once harvesting is completed, the feller buncher returns in five to 10 years, creating another eight-metre corridor in the centre of the spruce and aspen that had been left untouched, once again harvesting aspen eight metres on either side of the corridor. When the coniferous quota holder returns to the cutblock in 60 years, the spruce understory will have naturally taken over the stand. Because most of the mature aspen has been harvested, the spruce should have more than doubled their normal growth rate. It is then clearcut and the stand is allowed to naturally regenerate to aspen. In order to achieve natural spruce regeneration, Grover estimates that companies will need to leave only 20 to 40 seed trees per hectare. Using the one pass system, the feller buncher once again accesses the cutblock through eight metre corridors, harvesting aspen for eight metres on either side but leaving only five metres untouched between the corridors to avoid windthrow. Grover believes that managing spruce in this manner will yield the same growth objective. "I'm not sure that if you have a spruce seedling that is 50 centimetres by year seven, and one that is only 30 centimetres by year seven, that they won't have the same volume by year 80," she says. "No one has shown me different."

This proposed natural regeneration system has its advantages and disadvantages compared to clear cutting. The first advantage is that aspen and spruce maintain their symbiotic relationship. Secondly, experts estimate that protecting 800 understory spruce trees up to 40 years old-with time ly harvesting of the aspen-will yield an estimated savings of $9,000, versus attempting to regenerate spruce using traditional planting and tending methods. Thirdly, companies are not faced with expensive planting and tending costs associated with reforestation. Trials using this method have also impacted positively on wildlife. "The moose just love it," says Grover. "They have the aspen regen in the corridor, and cover right next to it." One disadvantage is that it will cost companies about $3 per hectare more in upfront harvesting costs to adopt this method versus clear cutting because harvesting is restricted to the trails. There is also a numerical break point when this method is not economically viable. "If you have less than 400 spruce stems per hectare," says Grover, "it's not viable. It is too expensive to protect a few spruce trees. You want a fully stocked stand." An obvious concern among sawmill operators who are used to the more simple-but expensive-method of replacing a harvested spruce tree with another spruce tree is in maintaining an adequate white spruce inventory using this new method. "If at any time I feel that I am short of white spruce, I can go into a mature aspen stand and plant spruce right there," says Grover. However, she recommends planting spruce in 20 to 30 year old aspen stands. "The reason I chose 20 to 30 years is because it seems that out there in the forest, natural recruitment of white spruce occurs either simultaneously with the aspen after a fire, or there is a lag time of 20 to 30 years." Once understory planting occurs, there is no additional maintenance required other than concerns with the snowshoe hare population.

AlPac is backing up its scientific bravado with actual trials and implementation of this new harvesting method. Management Forester Dave Cheyne is responsible for taking the operational trial results, and implementing them at the source management unit and total Forest Management Area (FMA) level. Formerly the federal government's expert on aspen, Cheyne will begin implementing this new harvesting and natural regeneration method this fall. He has been meeting with strategic planners from AlPac's two major coniferous quota holders, Vanderwell Contractors Ltd and Millar Western Forest Industries, as well as representatives from the government's Lands and Forests branch, for the past six months. So far, they have been successful in having the government and their coniferous partners "buy in" to this new method one step at a time. They have also held extensive inservice training for their logging contractors. "The ultimate plan is to do the whole Forest Management Area," says Cheyne. AlPac was granted timber harvesting rights on 60,000 square kilometres, or roughly a land base the size of Newfoundland, as a fibre resource about eight years ago. Less than half contains merchantable wood, and they are still in the process of conducting a full wood inventory. That is slated for completion in mid2001.

Their initial plan is to implement the new harvesting approach on one forest management unit, starting this fall with Vanderwell Contractors and leading to full implementation once their wood resource is fully inventoried. "It's a very large balancing act," says Cheyne. "It is trading back and forth. That's easy when you are trading only one or two blocks. But when you cut 10,000 hectares a year, you really have to start worrying about balancing the system." The main issue will be maintaining a reliable timber supply. "We have to make sure that we balance the pie at the bigger level," says Cheyne, "which means that everyone comes out a winner in wood supply and economics. These are the two main drivers we will have to implement, but biodiversity is an overriding issue on everything."

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The Long Haul

Deciduous fibre users such as AlPac are asking conifer users for a leap of faith with a new forest management proposal in Alberta.

By Tony Kryzanowski