Fig. 1. Annual temperature variations in ambient and standard OTC warmed plots in a conifer forest understory; (a) air temperature and (b) soil temperature. OTC, open-top chamber.

Fig. 2. Design of OTC-cable system. OTC, Open-top chamber; PAR, photosynthetically active radiation.

Fig. 3. Annual air temperature variations in ambient and OTC-cable system warmed plots in a conifer forest understory; (a) monthly daytime averages; and (b) monthly nighttime averages. OTC, open-top chamber.

Fig. 4. Annual soil temperature variations in ambient and OTC-cable system warmed plots in a conifer forest understory; (a) monthly daytime averages; and (b) monthly nighttime averages. OTC, open-top chamber.

Fig. 5. Annual variations in (a) PAR, (b) RH, (c) VPD, and (d) soil moisture in ambient plots and OTC-cable system warmed plots in a conifer forest understory; PAR, photosynthetically active radiation; RH, relative humidity; VPD, water vapor pressure deficit; OTC, open-top chamber.