CA-TPD

Soil CO2 emissions or soil respiration (Rs) data were measured at a 90-year old managed deciduous (Carolinian species) forest north of Lake Erie in southern Ontario, Canada. The forest site is part of the Turkey Point Observatory and has been associated with AmeriFlux and global Fluxnet initiatives, where it is known as CA-TPD. The forest is naturally regenerated on sandy terrain and abandoned agricultural land, and has been managed in the past. The dominant tree species include The stand is dominated by white oak (Quercus Alba), with secondary hardwood species including: red maple (Acer Rubrum), sugar maple (Acer Saccharum), black oak (Quercus Velutina), red oak (Quercus Rubra), white ash (Fraxinus Americana), yellow birch (Betula alleghaniensis) and American beech (Fagus Grandifolia). <br><br>Half hourly Rs was recorded using an automated soil CO2 flux measurement system from 2014 to 2019 (excluding winter months). It was comprised of three main components: the gas analyzer (hosted in an analyzer control unit) (LI-8100A), long-term measurement chambers (LI8100-104), and a multiplexer to allow for multiple chamber measurements (LI-8150) (LI-COR Lincoln, Nebraska, USA). Chambers were equipped with a soil temperature (Ts) and soil moisture (SM) probe at 5 cm depth installed outside of the collar. The soil collars had internal diameter of approximately 20 cm, a height of 11.5 cm, and a thickness of 1 cm. Each collar was inserted approximately 7-8 cm into the soil surface, with 3 cm remaining above. The measurement chambers remained open when not taking measurements. Throughout the growing season, any vegetation growth was removed from inside the collars to eliminate potential photosynthesis effects. <br><br>Tree density is 504 ± 18 tree per ha. Average tree height is 25.7m and diameter at breast height is 22.3 cm. Leaf Area Index is 8.0. The soil organic layer depth typically ranged from 2 to 6 cm. Topography in the area is predominantly flat with occasional 0.5-3.0% undulating slopes. The soil at the site is well drained with a low water holding capacity and classified as brunisolic grey-brown luvisols in the Canadian System of Soil Classification and is composed of ~98% sand. The climate in the region is cool temperate with a 30-year mean annual temperature of 8.0 °C and mean annual precipitation of 1036 mm.