Ecosystem monitoring and custom instrumentation

We can help you develop systems for measuring and reporting ecosystem processes automatically and from remote locations. Learn about TreeHuggers© - a system for making remote, automated measurements of tree growth and forest productivity.

How much carbon is my forest accumulating?

Is my plantation responding to drought?

Is the recent fertilizer application stimulating tree growth?

TreeHuggers

Tree girth and self-reporting band dendrometers... ... imagine measuring hundreds of trees in remote locations every day, every hour, every minute to track changes in girth with air and soil temperature and moisture...

Forest ecosystems play a central role in the global carbon cycle; they sustain approximately 80% of terrestrial net primary production (NPP) and 50% of global NPP (Whittaker 1975, Field et al. 1998) and are a major part of the terrestrial carbon sink that removes approximately 30% of anthropogenic carbon emissions each year (Canadell et al. 2007). Changes in this terrestrial carbon sink are readily estimated by measuring rates of tree growth. DeLucia's laboratory at the University of Illinois is developing low-cost, self-reporting dendrometers for automated measured of tree growth. Dendro-sensors (TreeHuggers) will be of immediate use to ongoing research to monitor changes in tree growth, carbon stocks and forest productivity globally. It is also reasonable to expect that TreeHuggers will be widely deployed by governments and those in the private sector involved in post-Kyoto carbon accounting activities.

The conservation of form exhibited by trees was described in the notebooks of Leonardo da Vinci and these conservative allometric relationships make simple measurements of changes in tree diameter enormously powerful. Because of the physical relationship between the diameter of pipes (vascular tissue) and the rate of water flow for a given change in pressure (transpiration), the relationship between tree diameter and the volume of wood, total leaf area and even root biomass is highly predictable (Whitehead et al. 1984, Enquist et al. 1998, DeLucia et al. 2000). For example, the diameter and "breast height" (1.45 m) predicts 98% of the variation in stem mass (converted from volume) and 92% of the variation in needle mass (Naidu et al. 1998). Thus, simple measurements of the change in stem diameter permit the calculation of the accumulation of biomass in trees.

Less appreciated than the power of measuring changes in diameter on monthly or annual time steps, is the wealth of information that can be obtained by making these measurements minute-to-minute over the course of a day. Though not readily visible to the naked eye, the stems of trees shrink and expand daily. The magnitude of this change, which can be several millimeters, is a function of the evaporative demand removing water from leaves and the supply rate of water to the roots (McLaughlin et al. 2003, Biondi et al. 2005) and measurements of diel changes in stem diameter provide a robust predictor of tree water status and transpiration rate (Intrigliolo and Castel 2005, Sevanto et al. 2008).

Dendrometer bands for measuring changes in tree girth were introduced early in the 20th century (MacDougal 1921, 1924). The bands consist of thin straps of metal placed around a tree, with one end passed through a collar and then connected back to itself with a spring - the change in dimension is read from a Vernier scale mounted on the band (http://www.nwrc.usgs.gov/Dendrometer/#1). This design still is in use, virtually unchanged, today (e.g. Moore et al. 2006). While effective and accurate, each tree must be physically visited for each measurements - for hourly measurements of different species in different forest plots, this is impractical. Building on previous efforts (e.g. Ofenthaler et al. 2001), we have designed affordable, automated dendrometer bands that self report wirelessly.

Automated, self-reporting dendrometer bands (TreeHuggers©) use a low cost but highly accurate linear string potentiometer to measure changes in the length of a stainless steel strap around a tree. The signal from the transducer is then broadcast to neighboring Densors arranged in a mesh network by wireless units employing ZigBee protocol. Zigbee has incredibly low power consumption compared to WiFi, enabling units to run for ~3 years on a small battery. Once mounted, each Densor measures changes in the circumference, increases or decreases, with an accuracy of ±50μm and reports this change via this wireless mesh network to a base station every 10 min. The base station provides 1 terabyte of data backup and can forward data at user defined intervals to any location via a satellite uplink. This automated approach to measuring tree growth will greatly enhance studies of tree physiology, forest carbon cycling and changes in phenology associated with global change.

References

Canadell JG, Le Quéré C, et al (2007) Contributions to accelerating atmospheric CO₂ growth from economic activity, carbon intensity, and efficiency of natural sinks. Proceedings of the National Academy of Science 104:18866 -18870

DeLucia EH, Maherali H, Carey EV (2000) Climate-drive changes in biomass allocation in pines. Global Change Biology 6:587-593

Enquist BJ, Brown JH, West GB (1998) Allometric scaling of plant energetics and population density. Nature 395:163-165

Field CB, Behrenfeld MJ, Randerson JT, Falkowski P (1998). Primary production of the biosphere: Integrating terrestrial and oceanic components. Science 281, 237-240

Intrigliolo DS, Castel JR (2006) Usefulness of diurnal trunk shrinkage as a water stress indicator in plum trees. Tree Phyiology 26:303-311

MacDougal DT (1921) Growth in trees: Carnegie Institute of Washington Publication No. 307

MacDougal DT (1924) Dendrographic measurements, in MacDougal, D.T., and Shreve, F. eds., Growth in trees and massive organs of plants: Washington, D.C., Carnegie Institute, p. 3-88

Moore DJP, Aref S, Ho RM, Pippen JS, Hamilton JG, DeLucia EH (2006) Annual basal area increment and growth duration of Pinus taeda in response to eight years of free-air carbon dioxide enrichment. Global Change Biology 12:1367-1377

Naidu SL, DeLucia EH, Thomas RB (1998) Constrasting patterns of biomass allocation in dominant and suppressed loblolly pine. Canadian Journal of Forest Research 28: 1116-1124

Offenthaler I, Hietz P, Richter H (2001) Wood diameter indicates diurnal and long-term patterns of xylem water potential in Norway spruce. Trees 15:215-221

Sevanto S, Nikinmaa E, Riikonen A, Daley M, Pettijohn JC, Mikkelsen TN, Phillips N, Holbrook NM (2008) Linking xylem diameter variations with sap flow measurements. Plant and Soil 305:77-90

Whitehead D, Edwards WRN, Jarvis PG (1984) Conducting sapwood area, foliage area and permeability in mature trees of Picea sitchensis and Pinus contorta. Canadian Journal of Forest Research 14:940-947

Whittaker RH (1975) Communities and Ecosystems, 2nd ed. MacMillan, NY. 385 pp

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