Forest Investment Account (FIA) - Forest Science Program
FIA Project R108077

    Maintenance of 15 to 25 year old site preparation and species trials
Project lead: Teresa Newsome (Ministry of Forests and Range)
Subject: Forest Investment Account (FIA), British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
1. Mapping the boundaries of EP904.02 (4 sites) in 2009/10 instead of 2010/11
2. Delaying the maintenance, flagging and mapping of EP1021.03 (1 site) until 2010/11
3. Completing maintenance on EP841.10 (1 site) in 2010/11.
4. Delaying the sign production for all trials until 2010/11

EP904.02 was assessed under FIA landbase funds in 2008/09. While the contractors were on site, in addition to measuring the trees, they completed the needed site maintenance. Now the GPS mapping of EP904.02 needs to be completed while the flagging is still fresh enough for the GPS contractor to follow not in 2010/11 as planned. Therefore, funds allocated for maintenance and mapping of EP1021.03 and sign production for all trial sites will be delayed until 2010/11. There also was some savings from not having to complete the maintenance and flagging of EP904.02 that was also planned for 2010/11. This money will be used to access and complete the maintenance on EP841.10 where maintenance and flagging could not be completed in 2008/09 due to access problems.

A number of trials studying combinations of site preparation techniques, vegetation control methods, and growth and response of different species and stock types were established in the old Cariboo Forest Region between 1984 and 1994. However, over the last few years, the focus of forest research has changed to larger silvicultural systems trials and the funding for these smaller projects has become scarce. Most trials have not been maintained within the last 10 years. In some cases assessments have been completed but money was not made available for maintenance activities. None of these trials are properly mapped using GSP which poses trial security issues. Without maintenance, the opportunity to learn from the long-term research data from these trials will be difficult. Extension products have been produced on data from the first 5 to10 years; however, these results may not be the same as those 20 to 25 years later. For example, some species such as spruce initially grow more slowly compared to others such as lodgepole pine. Ten-year response data comparing these two species on different site preparation treatments or in different ecological subzones may change. Also, the long-term effect of site preparation on tree performance needs to be determined to justify its current use.

There is a large variety of trials in this package. The EP841 series deals with tree response on site preparation techniques in dry to moist subzones (IDFdk and SBSdw). On these subzones seedling performance, particularly Douglas-fir (Fd), was either reduced or compromised by a combination of site factors, predominantly growing season frosts and drought. In some cases cattle are also an impediment to seedling establishment. Overall trial objectives were to mitigate the climatic extremes (and in one trial to reduce cattle activity) to enable seedling establishment and growth on these sites.

EP841.09, established in 1984, is one of the oldest trials and compares the response of 2 stock types, bareroot and container, for both Fd and lodgepole pine (Pl) on sites prepared with V-plows and hand screefing and on sites with no site preparation.

EP841.06 established in 1985, tests seven different forms of site preparation methods, hand screefing, leno patch scarification, disc trenching, ripping with a tooth, a ripper plow, a V-plow and no treatment on 3 species, Fd, Pl, and spruce (Sx) in the SBSdw1 and 2 species, Fd and Pl in the IDFdk3. The V-plow was not tested in the IDFdk3. The trial is replicated three times on 4 sites, two in each subzone.

Results from EP841.06 were used to develop EP841.07 to explore the more promising treatments. These included ripping, a small V-plow (1-m wide continuous screef that exposed mineral soil) and a rip down the middle of the 1-m screef and an untreated control. Each treatment was replicated 6 times on two sites (one in the SBSdw1 and the other in the IDFdk4). On each site, 3 replicates were fenced to keep cattle out of the trial area. The other was left unfenced to allow cattle grazing.

Finally, the most recent trial in this series, EP841.10, looks at mounding in the cold MSxv subzone on a site burned by a 1985 wildfire. Regeneration challenges in this ecosystem also include reducing frost damage, but cold wet soils and poor nutrition are more of a concern than drought. Therefore mounding was used to raise and warm the root environment and fertilizers were applied at time of planting. Two species (Sx and Pl) were planted into mounded and non-mounded micro-sites.

The two trials in the EP1021 series were both established in 1988 and they focus on the response of pine and spruce to different site preparation techniques in the ESSF. High elevation sites tend to be wet and brushy, therefore trial objectives included reducing brush competition and warming and drying the seedling root zone. At Fontaine creek, EP1021.02 compares mounding, screefing, brown and burn and herbicide applications. In this trial, 3 different spruce container stock types were tested (spring 1+0 313, and summer 2+0 313A and 415B). A brushing treatment was overlaid on the site preparation treatments providing results for seedling performance on sites just prepared and not brushed to sites prepared and brushed. EP1021.03 tests mounding and screefing compared to no treatment on the 2 species.

EP1066.03 established in 1988 looks at the rate and timing of glyphosate applications. The trial goals were to determine the amounts and dates where acceptable efficacy was obtained. The herbicide was applied at 3 rates on five dates. Vegetation development and the performance of Fd seedlings were compared on the treated areas and on an untreated control.

Finally the species trial established in 1988 compares the growth of western and Siberian larch and ponderosa pine to that of the acceptable local species (Sx, Fd, and Pl) across 4 subzones (IDFdk4, ICHmk2, SBSmw, ESSFwk1). The purpose of the trial was to test the species not native to the ecosystems with those that were native. Spruce was not planted on the IDFdk4 site and Ponderosa pine was not planted on the ESSFwk1 site.

All trials are fully replicated at least 3 times on each site and then where appropriate by site. They all use a basic randomized complete block design. In some trials the treatment units are further divided into split-block (EP841.06), split-plot (EP1021.03), split-split plot (EP841.07 and EP1021.02) and factorial (EP1066.02) designs.

These long term trials can also address a number of different objectives, often some that were not identified when the trials were established. Specifically in the current “FIA-FSP Timber Growth and Value Program” these trials broadly support basic research on growth and stand development. Data can be used to predict tree performance over a range of treatments and ecosystems. As well these projects will be particularly valuable in documenting the effects of climate change. Priority 7.1a is to “Predict the effects of climate change on the management and growth and yield of current and future stands.” In most cases these trials provide 20+ years of data occurring through the initial years of climate change and now into a more rapidly changing environment. Recording and contrasting the changes in growth, health issues and mortality will provide us with invaluable information as we try to predict the events in the coming years. In some trials, species are planted outside of their natural range. The performance of these trees will assist in deciding where species boundaries can be extended. For example western larch is performing particularly well in the ICHwk2 (EP904.02) and there may be potential for movement into that area. Also on three of the trials (EP841.07, EP841.10, and EP1021.02) climate stations were originally installed and have since been removed. However, re-installation at a later date can provide us with data on the changes on those particular sites.

Pertinent applicable results are still being obtained from all these trials. Often site preparation is professed to only affect very early stand development. However, data as old as 16 years indicate that there are continued significant differences in tree growth between site preparation treatments. Also comparisons between tree species on different subzones are providing data that can be used to select the optimal species combinations and perhaps allow the introduction of some non-native species. The data needs to be preserved so we can continue to learn from these installations. Presently, all trials and treatment units can be located. However, if they are left for much longer the investment and information from these trials will be lost. But even worse, results derived in the early years may not continue, leaving forest managers with incorrect perceptions regarding these treatments. Maintenance and mapping is critical to preserve and protect this information for future use.
Contact: Teresa Newsome, (250) 398-4408,

Updated August 16, 2010 

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