Herbaceous Vegetation Responses (1992–2004) to Restoration Treatments in a Ponderosa Pine Forest

Abstract

Ecological restoration treatments are widely applied in southwestern ponderosa pine forests to convert them to an open canopy structure similar to that found at the time of Euro-American settlement. An experiment was initiated in northern Arizona in 1994 to evaluate long-term ecosystem responses to 3 restoration treatments: 1) thinning from below (thinning), 2) thinning from below plus forest floor manipulation with periodic prescribed burning (composite), and 3) an untreated control. Results focus on total herbaceous and functional-group standing crop response to these restoration treatments. Pretreatment data were collected in 1992 and posttreatment responses were measured from 1994 through 2004. Total herbaceous standing crop was significantly higher on the 2 treated areas than on the control over the entire posttreatment period, but did not differ between the thinning and composite treatments. Plant functional groups responded differently to treatments and to drought. In general, the graminoid standing crop responded within several years after the initial treatments and continued to increase through time, until a series of severe droughts reduced standing crop to pretreatment levels. C 3 graminoids dominated the standing-crop response, of which bottlebrush squirreltail (Elymus elymoides (Raf.) Swezey ssp. elymoides) was the primary contributor. C 4 graminoids had a minimal response to restoration treatments, possibly because they were less abundant before the experiment began or because they were adversely affected by autumn burning. Legumes and forbs exhibited a 4-5 year lag before responding to the thinning and composite treatments. Annual and biennial plants showed a large biomass increase approximately 5 years after implementation of the composite treatment. The restoration goal of optimizing herbaceous standing crop must be weighed against the competing goals of increasing the abundance of specific functional groups, increasing biodiversity or rare plants, and managing invasive plant species.

Small mammal community maintains stability through compensatory dynamics after restoration of a ponderosa pine forest

“…We observed opposite responses by tassel-eared squirrels and golden-mantled ground squirrels, as the former is associated with mature pine trees for nesting and foraging (Patton 1977), while the latter uses open meadow-like habitat (Bartels and Thompson 1993); and by woodrats and voles, as woodrats are associated with shrub cover and down wood (Block et al 2005), while voles use meadow-like understory (Bagne and Finch 2009). Overall, six species responded positively to the disturbance event, which is logical given that ponderosa pine forests and its species historically experienced the natural disturbance of fire every 2-20 years (Covington and Moore 1994), and thinning and fire can effect some habitat features (i.e., understory production) in similar ways (Moore et al 2006, Schwilk et al 2009). Two species responded negatively to thinning, including woodrats, which probably experienced a lack of cover at the thinned sites, and pocket gophers, which may have been negatively affected by the soil compaction associated with thinning.…”

“…Following thinning and reduction of basal area, ponderosa pine forests experience an increase in understory vegetation in terms of cover and diversity in as little as 2 years posttreatment (Moore et al 2006). In addition, down wood (slash) is usually left onsite for 1-2 years before being burned, adding a source of cover to an otherwise disturbed site.…”

Initial Development of Forest Structure and Understory Vegetation after Clear-cut in Pinus densiflora Forest in Southern Gangwon-do Province

“…산림을 대상 으로 한 벌채 작업은 식물 종 다양성의 대부분을 포함하 고 있는 하층 식생의 종풍부도를 증가 (Metlen and Fiedler, 2006;Dodson et al, 2008), 감소 (Metlen et al, 2004;Fulé et al, 2005) 또는 뚜렷하지 않은 (Nelson et al, 2008) 변화 등 다양한 반응을 가져온다. 또한 종 피도 변화는 서식처 선호성, 생육형과 같은 식물 기능군에 따라 다양하게 나 타나는데, 이것은 종 별 교란 내성 및 회복력의 차이가 있 음을 보여준다 (Halpern, 1988;Metlen et al, 2004;Metlen and Fiedler, 2006;Moore et al, 2006). Table 2.…”

Ecological responses of natural and planted forests to thinning in southeastern Korea: a chronosequence study

“…Responses of species cover also varied among functional types, suggesting differences in tolerance or resilience to disturbances (Halpern 1988, Metlen et al 2004, Metlen and Fiedler 2006, Moore et al 2006. In understory vegetation, various consequences of secondary succession after forest management are predictable, but the emerging patterns and pathways of disturbed forests are not yet clarified in natural and planted forests in Korea.…”