Terrestrial

Forest tree, woody debris, and soil inventory data from long-term research plots at the University of Michigan Biological Station

Abstract: 

Disturbances to forests, such as logging or wildfires, typically lead to large losses of carbon and nutrients from both the plants and soils of the ecosystem. Virtually all forests are in some state of recovery from such disturbances, whether caused naturally or by humans. Knowledge of the time required for a forest to recover its original amounts of carbon and nutrients after a disturbance is not complete, nor is an understanding of how regrowing plants, recovering soils and the year to year variation in climate interact to control recovery as a forest ages. This project takes advantage of long existing research plots in forests at the University of Michigan Biological Station to figure out how changes in forest structure, carbon and nitrogen contents of the forests, and variations in climate act together through time to influence how fast trees grow, nitrogen is retained, and carbon is captured and stored in forests. Scientists and students will make regular measurements of the types of trees, their stem sizes and mass, their patterns of leaf arrangement, the amounts of carbon and nitrogen in soils, and other factors in five forest that were cut and burned in 1936, 1948, 1954, 1980, and 1998 and so today range from 15 years to 115 years old. Several nearby much older forests will also be sampled. This will let the project link disturbances, climate and ecology for forests that are broadly representative of those across the northern United States, Canada, Europe and Asia.

Short name: 
LTREB
Methods: 

Researchers used dbh tapes and / or calipers to measure the diameter at breast height (dbh, 1.37 above ground) of every tree within the boundaries of each plot. For some plots, the location (azimuth and distance) from plot center (or corner post) was determined. For some plots, dbh values were assigned as classes (e.g., 6-8 cm dbh) and the number of stems of each species within each diameter class was recorded.

Below are the two equations used to estimate aboveground biomass and height of trees. See the Allometric_equations.csv file for constants used in these two equations according to species. In cases where the species is not listed in the table, the generic constants were used.

AG biomass = a * dbh^b * height^c
height = a*dbh^b

Data sources: 
LTREB Above Ground Biomass
LTREB Saplings Inventory 2014
LTREB Coarse Woody Debris
LTREB Allometric Equations

Ozone Concentations and Ozone Flux 2002-2005 at the UMBS PROPHET Tower

Abstract: 

Measurements of ozone, sensible heat, and latent heat fluxes and plant physiological parameters were made at a northern mixed hardwood forest located at the University of Michigan Biological Station in northern Michigan from June 27 to September 28, 2002. These measurements were used to calculate total ozone flux and partitioning between stomatal and non-stomatal sinks. Total ozone flux varied diurnally with maximum values reaching 100 8mol m-2 h-1 at midday and minimums at or near zero at night. Mean daytime canopy conductance was 0.5 mol m-2 s-1. During daytime, non-stomatal ozone conductance accounted for as much as 66% of canopy conductance, with the non-stomatal sink representing 63% of the ozone flux. Stomatal conductance showed expected patterns of behaviour with respect to photosynthetic photon flux density (PPFD) and vapour pressure defecit (VPD). Non-stomatal conductance for ozone increased monotonically with increasing PPFD, increased with temperature (T) before falling off again at high T, and behaved similarly for VPD. Day-time non-stomatal ozone sinks are large and vary with time and environmental drivers, particularly PPFD and T. This information is crucial to deriving mechanistic models that can simulate ozone uptake by different vegetation types.

These measurements and post processing were repeated in 2003, 2004, and 2005 at varying time intervals.

Short name: 
O3 Flux 2002-2005
Data sources: 
Ozone Concentations and Ozone Flux 2002-2005 at the UMBS PROPHET Tower
Methods: 

Above-canopy fluxes of ozone were measured from the 35 m PROPHET tower. The ozone sample inlet and sonic anemometer were located 33 m above ground and the air sample was transported to the detector via a 40 m length of 5/8-in. Teflon tubing. The residence time from sample inlet to the detector in the laboratory at the base of the tower was typically less than 25 s. Wind speed and direction (Wind Monitor-RE, R. M. Young Company, USA), pressure (Barometric Pressure Sensor Model 61201, R. M. Young Company, USA), temperature and relative humidity (MP100, Rotronics Instrument Corp, USA) are measured continuously at the top of the PROPHET tower (Carroll et al., 2001). An open-path infrared gas analyzer (IRGA) (Auble and Meyers, 1992) was co-located with the sonic anemometer (K- configuration, ATI, USA) to measure water and CO2 concentration (Pressley et al., 2005). Photosynthetic photon flux density (PPFD) (LI-190SZ, Li-Cor, USA) was measured on the adjacent Ameriflux tower (Schmid et al., 2003), which is located 132 m north–northeast of the PROPHET tower.

Ozone was measured using the University of Michigan Multichannel Chemiluminescence Instrument (UMMCI), a custom-built chemiluminescence detector (e.g. Ridley, et al., 1992), illustrated in Fig. 1. The detector consists of a gold-plated 316 stainless-steel reaction vessel (RV, 17 cm3, maintained at 35 degrees C, design by B. A. Ridley, Ridley, et al., 1992), a red-sensitive Hamamatsu R1333 photomultiplier tube (PMT, operated at 5 degrees C), and zeroing volume (ZV, maintained at 100 degrees C) containing 0.5% Pd on Al ozone destruction catalyst (Degussa Metals Corp.).