Restoration planting options for limber pine (Pinus flexilisJames) in the Southern Rocky Mountains¹

Limber Pine Regeneration and White Pine Blister Rust in the Central and Southern Rocky Mountains

“…Linear regression indicated a positive relationship between limber pine seedling density and limber pine tree density (Figure 5), an expected result, because mature, cone-bearing trees provide the seed source for regeneration for seeds falling to the ground and provide microsite cover for seeds cached or fallen (Casper 2012). Whitebark pine, another five-needle pine, regeneration is positively associated with total stand density, as well as whitebark pine density (Larson and Kipfmueller 2010).…”

“…For greater survival success, Smith et al (2011) recommended outplanting of seedlings, in clusters, instead of seed. Our results indicate that seedlings should be planted next to microsite objects, particularly rocks and trees, especially for protection at higher elevations or on harsh sites (Maher and Germino 2006, Smith et al 2011). Casper et al (2016 recommended planting on the north or west side of objects.…”

“…Our results of average terminal growth measurement indicate that the terminal growth rate increases as seedling height increases, but on some sites, terminal growth may be very slow or delayed until release. In sites in Colorado and Wyoming, Casper (2012) found limber pine seedlings between 30 and 140 cm tall to range in age from about 12 to 41 years. In a study by Veblen (1986), median age of limber pine seedlings (Յ1.4 m tall) (n ϭ 8) on a site in the Front Range of Colorado was 63 years and ranged from 47 to 115 years, supporting the typical slow growth rates of conifers, particularly when suppressed.…”

“…Facilitating and maintaining stands of limber pine are essential for promoting natural selection to encourage the development of resistance mechanisms to WPBR (Loo 2009 limber pine during treatments, removal of competing vegetation, and creation of openings (Burns et al 2008, Coop and Schoettle 2009, Casper et al 2016. Managing limber pine stands, particularly those with little WPBR impact, for multiple age classes may allow for increased regeneration (Schoettle and Sniezko 2007) and would provide some resiliency against stand-level mountain pine beetle mortality.…”

Epidemiology of white pine blister rust on limber pine in Colorado and Wyoming

“…It is unlikely that limber pine will be greatly impacted on Type 1 sites (long presence/low incidence). Encouraging regeneration, planting seedlings and/or pruning cankered branches may be feasible options on such sites (Casper, Jacobi, Schoettle, & Burns, ; Jacobi, Pineda Bovin, Burns, Crump, & Goodrich, ; Schoettle, Jacobi, Waring, & Burns, in review). Disease intensification and mortality will likely continue on Type 2 sites (long presence/moderate‐to‐high incidence) such as the Sweetwater Basin and Pole Mountain (Table ).…”