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100-year ponderosa pine assisted migration study at the Fort Valley Experimental Forest

Date: October 12, 2017

Perspectives from the historical provenance study at the Fort Valley Experimental Forest


Background

A study of ponderosa pine from different locations throughout the western United States was started in the 1910s by Gustaf A. Pearson. Seed was collected from 18 National Forests, grouped into two ponderosa pine varieties: Scopulorum and Ponderosa, and planted at the Fort Valley Experimental Forest (FVEF), which is 2237 meters (7340 feet) in elevation. Survival was monitored until 1919, then subsequently measured in 1928, 1951, 1964, and 1995. Tree heights were measured in 1928 and heights and diameters were measured in 1964 and 1995–1996. 

Research

The purpose was to assess the genetic diversity and adaptation patterns, and to improve forest management of ponderosa pine. We assumed that tree size is a function of age, density, climate, and provenance (the population of trees growing from a geographic location).

There were three hypotheses:

  1. Provenances from climates similar to FVEF will have higher survival rates. 
  2. Provenances from climates similar to FVEF will have better growth rates. 
  3. Provenances from wetter sites will show more sensitivity to local climate variations.

Images from the study sites show location and example of plot.
Images from the study sites show location and example of plot.

In 2014, we measured the height, diameter, and core samples of selected trees. Tree data were correlated with long-term weather data at the study location and at the original source of the contributed seeds. In 2016, we measured density around those selected trees by stem mapping the entire study plot. Analysis of that stem mapping is continuing. In 2017, we are analyzing the cores and matching the core data with concurrent weather data.

Key Findings

  • All Ponderosa ponderosa var. ponderosa died. 
  • More northerly or higher elevation material performed better.
  • Greater variation between original source climate and the climate at the FVEF study site impacts survival and growth.

New publications forthcoming.



Principal Investigators: 
Forest Service Partners: 
Mary Frances Mahalovich, Regional Geneticist, R1-R4, Moscow, ID
Research Location: 
Fort Valley Experimental Forest