In this second article on the topic of capturing secondary values from longstanding Canadian Forest Service (CFS) research and development legacy sites—many established over the past 30 to 50 years—let’s focus now on microsite trials where the initial goal at time of establishment was head-to-head treatments followed by comparison of outcomes.

Initially, these microsites were intensive research and development trials established close to operational scale that addressed a very specific issue of the day over the short term.

Now we can extend the initial capital investment made by CFS and its many partners to establish these trials by evaluating what we can learn from them in an effort to tackle current issues like fire vulnerability and risk reduction, access to fibre, rotation age, etc.

Our first example is of a nursery stock microsite trial established in 2000 in the Sulphur Lake area of Central Alberta, researching a variety of different site preparation treatments which included horizontal bed mixing, elevated bed mixing, mounding, scalping, and a no-treatment control site.

In addition to the various site preparation treatments, the site was also established as a nursery stock trial. So, it represents 11 different Styroblock stock types that could provide an advantage early on for survival and establishment to a 1.3 metre height.

Initially, the white spruce/aspen mixedwood site was clearcut in the winter of 1999/2000 with the aspen component left to regenerate naturally. The white spruce were planted on the treated microsites at 2.5 X 2.5 m spacing either on mounds, scalps, no-treatment or on intermittent mixed beds created by a Grizz mixer (elevated bed) or a MeriCrusher mounted on an excavator and powered hydraulically.

The pictorial images shown here illustrate the site preparation pattern, tools used and the aerial view of the site at present time.

The second example represents a ‘mixedwood by-design’ trial, which incorporates a combination of afforestation as well as natural forest strategies and silviculture treatments.

It was established in Central Alberta in 2001, consisting of a combination of selected hybrid poplar and hybrid aspen planted with white spruce on a fully site-prepared area that resulted in a consistent ground medium. The ground slash, stumps, and upper organic (L/F) layer were sheared during winter with a shear blade mounted on a 300 hp tracked bulldozer. This was followed by a high-speed horizontal bed mixer in the spring. This mixing consisted of a 325-rpm toothed, drum-type treatment using a 2.4 m wide MeriCrusher powered by the PTO of a 200 hp wheeled tractor. It created a consistent and deep mix through a combination of approximately 35 cms of organics and silty-clay loam mineral soil.

The trees were planted on a variety of different bed types with a distribution of the hybrid hardwoods as well as white spruce in a pattern where the spruce were planted either in-between each hardwood planting or in complete rows distributed throughout the site, to diversify the values through establishing a mixedwood and to maximize fibre growth.

The third example is a microsite trial composed of lodgepole pine located in the Foothills Natural Region in the Whitecourt, Alberta area.

This site was established in 1993 after clearcut harvesting in what was a moderately deep organic mixedwood site of lodgepole pine, spruce and aspen, with sandy loam soil.

The site prep treatments included horizontal and elevated bed mixing, a combination of disc trenching in single and double patterns, as well as selective mixing using a VH mulcher, an excavator-mounted elevated mix patch attachment, and no-treatment control.

The lodgepole pine planting took place in the spring of 1993, a year after site preparation, all at a spacing of 2 X 2.5 m.

The aerial images included here show the treatment replications and microsite treatment patterns taken from a drone flying 70 metres above ground, indicating the various impacts on the trees. They currently vary from 7 to 13 m in height, depending on the treatments.

For more information, contact Derek Sidders, Legacy Program Coordinator and Technology Advisor, Science Partnerships and Knowledge Mobilization Division, Canadian Forest Service, at derek.sidders@nrcan-rncan.gc.ca.