Protecting western redcedar from deer browsing-with a passing reference to TRP channels

Abstract

This editorial is about tree farming. It proposes to test in an experiment whether co-planting (in the same hole) western redcedar (WRC, Thuja plicata) with Sitka spruce (Picea sitchensis) protects WRC seedlings from wildlife browsing. This sustainable protection method is an alternative to the traditional use of mechanical devices and big-game repellents. Many repellents contain transient receptor potential (TRP) agonists, such as capsaicin, a TRP vanilloid-1 agonist. This editorial also delivers a puzzle: while herbivores avoid capsaicin, why do people living in hot climates consume large quantities of it (in chili peppers)?

Keywords: AITC; AITC, allyl isothiocyanate; ATFS, American Tree Farm System; OSU, Oregon State University; RMZ, riparian management zone; TRP, transient receptor potential; TRPA1; TRPV1; WFFA, Washington Farm Forestry Association; WRC, western redcedar; WSARE, Western Sustainable Agriculture Research and Education; capsaicin; deer browsing; picea sitchensis; repellants; repellents; sitka spruce; spicy foods; sustainability; thuja plicata; transient receptor potential channels; tree farming.

Figure 1.

The so-called “Quinault-Lake Cedar.” This is the largest known WRC in the world, with a 19.5 ft (5.94 m) diameter at breast height and an estimated wood volume of 17650 ft (500 m³). It is located ∼50 mi (80 km) from Tree Fever. Photo by Wsiegmund, Wikimedia Commons, reproduced under a CC-BY 2.5 license.

Figure 2.

Nuu-chah-nulth (Nootka) tribesman, likely a whaler, wearing traditional cedar-bark clothes, Washington State, c. 1910. Photo by Edward S. Curtis, Library of Congress, Washington, DC.

Figure 3.

The author installing a Vexar tube around a WRC seedling with two cable ties fixed to a bamboo stick. Tree Fever research plantation, March 2015. This photo and photos shown in figures 4 and 6 are by Nancy and/or Andrej Romanovsky.

Figure 4.

Princess Candy and her guard, Sitka. A seedling of WRC co-planted in the same hole with a seedling of Sitka spruce at the Tree Fever research plantation (A). Young WRC and Sitka spruce that were seeded naturally on Tree Fever in very close proximity to each other, thus resembling co-planting in the same hole (B). In both photos, some branches of the WRC seedling are shown with red arrows, and some branches of the spruce seedlings are shown with cyan arrows. The naturally seeded Sitka is only 2 ft (0.6 m) high, but it already shows deformities, possibly due to weevil-associated damage, even though most Sitka trees are damaged by the weevil after they become 5 ft (1.5 m) high.

Figure 5.

This rotten Sitka spruce was removed from Tree Fever during the 2014 rehab harvest. The tree had an 8.9 ft (2.7 m) diameter at breast height. Photo courtesy of David Houk.

Figure 6.

Before and after. Low-grade hardwoods in the narrow strip of land between the West Satsop RMZ and main Douglas fir stands before the rehab harvest (July 2014) (A). The thickest trunks in the front have a diameter of ∼1.5 in (4 cm). After the harvest, site preparation, and planting, this strip of land became a WRC research plantation (March 2015) (B).