Predicting field performance of Douglas-fir seedlings: comparison of root growth potential, vigor and plant moisture stress

Abstract

Application. The field performance of Douglas-fir seedlings can be strongly influenced by their physiological condition when they are outplanted. Seedlings damaged or with low vigor have a much greater chance of dying in the field, or at best, of growing slowly during initial establishment. Being able to identify and discard lots of poor quality can help prevent plantation failures by eliminating seedlings that have little or no chance for acceptable field growth or survival. Three methods of evaluating seedlings were compared, and all successfully predicted field performance. If such evaluations were applied to screen seedling lots prior to planting (especially those suspected of injury), reforestation in the Douglas-fir region could be improved.Abstract. Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] seedlings were evaluated by three measurements of seedling quality -root growth potential or RGP, vigor, and plant moisture stress or PMS -and the results were correlated with subsequent field performance. Measurements made by each method were significantly (p_< 0.05) correlated with first-and second-year survival and terminal height growth. Seedlings from lots that grew many new roots during a 28-day interval in a growth room (RGP evaluation) or that survived for 6 weeks in the growth room and initiated rapid budburst (vigor evaluation) or whose plant moisture stress values remained fairly constant during 1 week after potting (PMS evaluation) had the greatest field survival and height growth.The RGP evaluation was the best predictor of first-year height growth, while the vigor evaluation was the best predictor of first-and second-year survival. All evaluations predicted second-year height growth equally well.These results demonstrate that all three evaluations can be successfully used to predict field performance of Douglas-fir seedlings. Each has its advantages and limitations, and none can be considered "best".

Planting stock performance: Site and RGP effects

“…la). For Douglas-fir, the absence of a relationship between RGP and survival is inconsistent with previous studies (McCreary and Duryea 1987;. Although RGP ranged from 0 to more than 30 new roots per seedling, most of the batches used had RGP levels greater than 0 but less than 10 new roots per seedling.…”

Heat damage in boxed white spruce (Picea glauca [Moench.] Voss) seedlings: Its pre-planting detection and effect on field performance

“…1986;McCreary and Duryea 1987 ;Koppenaal and Colombo 1988), immersed directly in heated water (Colombo and Timmer 1992), or only use needle sections (Burr et al . 1993).…”

“…1993). Some studies have investigated the effects of short-term temperature exposure in the range of 10-40 ° C (McCreary and Duryea 1987 ;Koppenaal et al . 1991), but none in which boxed stock was exposed immediately after removal from cold storage .…”

National Fire Plan Research and Development 2004-2005 accomplishment report

“…Threshold values could also be determined for other species for which the positive relationship between RGP and field performance has been found (Burdett et al 1983(Burdett et al , larsen et al 1986 Target X Root Growth Potential Duryea 1987). These values would be helpful as a general guide of stock quality but would not predict survival under specific field conditions because of the reasons stated earlier.…”