Forest Investment Account (FIA) - Forest Science Program
FIA Project Y081054

    Effects of intensive fertilization on timber and non-timber resources
Project lead: Brockley, Rob (BC Ministry of Forests and Range)
Contributing Authors: Berch, Shannon M.; Brockley, Robert P.; Simpson, David G.; van Thienen, Frank J.; Fielder, Peter P.
Subject: Forest Investment Account (FIA), British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
Catastrophic lodgepole pine mortality caused by the MPB is creating serious future timber supply challenges for the forestry sector in the BC interior. Without strategic intervention, significant timber supply shortfalls are forecast for many interior forest management units. Because virtually all trees to be harvested from interior forests within the next 50 years are already growing, forest planners and practitioners are seeking ways to accelerate the development of immature stands so that they may be harvested sooner. Fertilization is a proven method for increasing harvest volume and accelerating the operability of established stands. A large-scale operational fertilization program has recently been implemented in interior TSA’s that are heavily impacted by the MPB. During the past 20 years, extensive research has been undertaken to determine the nutritional status of immature forests in the B.C. interior and to document the effectiveness of “conventional” fertilization (i.e., a single fertilizer application) on improving tree and stand growth across a wide range of sites. These studies have confirmed that nitrogen (N) deficiencies are widespread throughout the region, and that N additions often have a substantial positive effect on tree and stand growth. Other nutrient deficiencies, either induced or aggravated by N fertilization, have also been implicated as factors limiting the growth response of some N-fertilized interior forests. Recent studies have confirmed that growth responses may be enhanced if sulphur (S) and/or boron (B) is combined with N in fertilizer prescriptions. A single fertilizer application typically produces only a temporary increase in tree and stand growth. However, fertilization research in boreal and sub-boreal forests indicates that sustained growth responses are achievable by repeatedly fertilizing young conifer stands. For example, the growth of Norway spruce in Swedish “optimum nutrition “ studies has been doubled or tripled by frequent additions of balanced fertilizers, and growth projection models estimate that large reductions in rotation lengths are possible. Large, but less spectacular, growth responses have also been documented following repeated fertilization of several Pinus species. In the B.C. interior, large and sustained productivity gains in young pine and spruce forests would be of huge benefit in addressing timber supply challenges such as the amount, and timing, of future harvests. However, it is important to document the magnitude of potential growth gains so that realistic expectations can be included in timber supply analyses and AAC volume target objectives. Long-term response data from well designed, area-based field experiments are needed to fully document the potential growth and yield benefits of permanently removing nutritional constraints in interior forests. Also, the effects of rapid growth on wood quality and value needs to be evaluated, as do the effects of repeated fertilization on above-ground timber and non-timber forest resources. To what extent can repeated fertilization potentially mitigate looming timber supply shortfalls in the BC interior? What are the potential long-term ecological consequences of adding large quantities of nutrients to Interior forests? To provide reliable answers to these questions, the BC Ministry of Forests Research Branch initiated the “maximum productivity” research project (EP 886.13) in 1992 with funding provided by the Canada-British Columbia Forest Resource Development Agreement (FRDA II). Subsequent funding was provided by Forest Renewal BC and Forestry Innovation Investment Ltd. Current funding being provided by FIA-FSP (Y073101) expires in 2006/07. Eight lodgepole pine and interior spruce “maximum productivity” field installations (5 pine and 3 spruce) were established in young plantations and juvenile-spaced, harvest-origin stands in central and north-central BC between 1992 and 1999. The three spruce installations were established in three different subzones of the SBS biogeoclimatic zone, representing a broad range of climatic conditions. Three of the lodgepole pine installations were also established in the SBS zone, while the other two remaining pine sites are in the ESSF and MS zones. Two of the lodgepole pine installations were recently abandoned after being severely attacked by the MPB. The growth and yield objectives of the “maximum productivity” project are to compare the effects of different regimes and frequencies of repeated fertilization on stand growth and development. The strictly controlled environments at these study sites also provide excellent opportunities for documenting the effects of large nutrient additions on several above- and below-ground timber and non-timber resources. In collaboration with a multi-disciplinary team of scientists and graduate students, several ancillary studies have been undertaken at selected study sites. These studies have examined the effects of repeated fertilization on: 1) spruce terminal weevil activity, 2) foliar pathogens, 3) soil biota activity and diversity, 4) C sequestration, 5) soil CO2 emissions, 6) litterfall, litter quality and decomposition, 7) forest floor and mineral soil properties, and 8) understory characteristics. Possible future ancillary studies include examination of the effects of repeated fertilization on wood quality and value. At each site, six treatments are replicated three times for a total of 18, 0.164-ha treatment plots. The six treatments are: 1.Control (i.e., not fertilized) 2.NB – fertilize every 6 years with (kg/ha): 200N, 1.5B 3.NSB – fertilize every 6 years with (kg/ha): 200N, 50S, 1.5B 4.Complete – fertilize every 6 years with (kg/ha): 200N, 100P, 100K, 50S, 25Mg, 1.5B 5.ON1 – yearly fertilization to maintain foliar N concentration at 1.3% 6.ON2 – yearly fertilization to maintain foliar N concentration at 1.6% The ON1 and ON2 treatments are patterned after Scots pine and Norway spruce “optimum nutrition” experiments in Sweden, and typically receive 50-75 kg N/ha and 100-150 kg N/ha, respectively, each year. Other nutrients are added periodically to provide an appropriate nutrient balance and to minimize growth limitations caused by secondary deficiencies. This long-term research project is providing the reliable, scientifically based estimates of productivity and sustainability impacts of high input silviculture to ensure that appropriate stand management treatments are used to achieve specific timber and non-timber yield and product objectives. The project addresses the FSP Theme 2.2a within the Timber Growth and Value Program.
Related projects:  FSP_Y092054FSP_Y103054


Executive Summary (0.1Mb)
Extension Note (March) (0.4Mb)
Fertilization Report (0.4Mb)
Extension Note (September) (0.3Mb)
Forest Ecology Workshop Report (0.1Mb)

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Updated August 16, 2010 

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