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Effects of Sheep Grazing on Tree Seedlings in a Northern Idaho Conifer Plantation Item Info
![Two studies were conducted near Moscow, Idaho over 4 years to evaluate the effects of sheep grazing intensity on Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) and sheep season of use on Douglas-fir and Ponderosa pine (Pinus ponderosa Dougl. ex laws.). The grazing intensity study was conducted on a 4-year-old conifer plantation during 1991- 1992. Four pastures were grazed plus an ungrazed control. Grazing intensity averaged over the 2 years ranged from65 to 78.5% utilization of the available forage. Tree seedling height growth in the heaviest grazed treatment did not differ from the ungrazed control (p>0.10), and was at least 35% greater (p≤0.10) than the other grazed treatments. Diameter growth of tree seedlings in the heaviest grazed treatment exceeded the other 4 treatments by 32-49% (p≤0.10). Lateral browsing and terminal clipping did not differ (p≥0.10) in the heaviest grazed treatment compared to the ungrazed control in both years of the study. Treatments did not differ (p>0.10) in rodent damage, trampling, or tree seedling mortality. In 1991, about 3-4 weeks after grazing ceased, lower tree seedling xylem water potential (p≤0.10) and greater soil moisture levels (p≤0.10) were recorded in the heaviest grazed treatment compared to ungrazed control. The season of grazing study was conducted during 1993-1994 on a portion of the same site as the aforementioned study. The treatments used during the study were early and late summer grazing and an ungrazed control. Greater lateral browsing (p≤0.10) and terminal clipping (p≤0.10) of Douglas-fir occurred in the late treatment of 1993 compared to early and control treatments. In 1994, lateral browsing did not differ (p>0.10) among treatments and greater terminal clipping (p≤0.10) occurred in the early grazed treatment compared to the late and control treatments. Douglas-fir seedling damage was reflected in reduced (p≤0.10) height and diameter growth for both early and late grazed treatments compared to the ungrazed control. However, Douglas-fir seedlings in the early treatment of 1994 that did not have their terminal buds clipped by sheep did not differ in height growth compared to the control (p>0.10). Browsing damage of ponderosa pine in the early and late grazed treatments did not differ from the ungrazed control (p>0.10). Height growth had a significant (p≤0.10) treatment × year interaction. In 1993 there was no difference in height growth among treatments (p>0.10). However, in 1994, both the early and late treatments had greater height growth compared to the ungrazed control (p≤0.10). Diameter growth was greater (p≤0.10) in the early and late grazed treatments over control. Ponderosa pine seedling growth benefited equally form either grazing treatment.](https://objects.lib.uidaho.edu/uief/small/uief_0101_sm.jpg)
- Title:
- Effects of Sheep Grazing on Tree Seedlings in a Northern Idaho Conifer Plantation
- Creator:
- MacRae, Steven J.
- Date Created:
- 1996-04
- Description:
- Two studies were conducted near Moscow, Idaho over 4 years to evaluate the effects of sheep grazing intensity on Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) and sheep season of use on Douglas-fir and Ponderosa pine (Pinus ponderosa Dougl. ex laws.). The grazing intensity study was conducted on a 4-year-old conifer plantation during 1991- 1992. Four pastures were grazed plus an ungrazed control. Grazing intensity averaged over the 2 years ranged from65 to 78.5% utilization of the available forage. Tree seedling height growth in the heaviest grazed treatment did not differ from the ungrazed control (p>0.10), and was at least 35% greater (p≤0.10) than the other grazed treatments. Diameter growth of tree seedlings in the heaviest grazed treatment exceeded the other 4 treatments by 32-49% (p≤0.10). Lateral browsing and terminal clipping did not differ (p≥0.10) in the heaviest grazed treatment compared to the ungrazed control in both years of the study. Treatments did not differ (p>0.10) in rodent damage, trampling, or tree seedling mortality. In 1991, about 3-4 weeks after grazing ceased, lower tree seedling xylem water potential (p≤0.10) and greater soil moisture levels (p≤0.10) were recorded in the heaviest grazed treatment compared to ungrazed control. The season of grazing study was conducted during 1993-1994 on a portion of the same site as the aforementioned study. The treatments used during the study were early and late summer grazing and an ungrazed control. Greater lateral browsing (p≤0.10) and terminal clipping (p≤0.10) of Douglas-fir occurred in the late treatment of 1993 compared to early and control treatments. In 1994, lateral browsing did not differ (p>0.10) among treatments and greater terminal clipping (p≤0.10) occurred in the early grazed treatment compared to the late and control treatments. Douglas-fir seedling damage was reflected in reduced (p≤0.10) height and diameter growth for both early and late grazed treatments compared to the ungrazed control. However, Douglas-fir seedlings in the early treatment of 1994 that did not have their terminal buds clipped by sheep did not differ in height growth compared to the control (p>0.10). Browsing damage of ponderosa pine in the early and late grazed treatments did not differ from the ungrazed control (p>0.10). Height growth had a significant (p≤0.10) treatment × year interaction. In 1993 there was no difference in height growth among treatments (p>0.10). However, in 1994, both the early and late treatments had greater height growth compared to the ungrazed control (p≤0.10). Diameter growth was greater (p≤0.10) in the early and late grazed treatments over control. Ponderosa pine seedling growth benefited equally form either grazing treatment.
- Document Type:
- Thesis
- Library Call Number:
- SF375.4.I2M27 1996
- Subjects:
- Flat Creek sheep grazing seedling effects conifer plantation grazing effects North Idaho forest ecology
- UIEF Unit:
- Flat Creek
- Location:
- UIEF; Flat Creek
- Latitude:
- 46.822278
- Longitude:
- -116.768873
- Department:
- Department of Forest Resources
- Type:
- text
- Format:
- application/pdf
Source
- Preferred Citation:
- "Effects of Sheep Grazing on Tree Seedlings in a Northern Idaho Conifer Plantation", UIEF Research Exchange, University of Idaho Library Digital Collections, https://www.lib.uidaho.edu/digital/uief/items/uief_0101.html
Rights
- Rights:
- In copyright, educational use permitted.
- Standardized Rights:
- http://rightsstatements.org/vocab/InC-EDU/1.0/