There are four common reasons to set up a monitoring system in a forest:
- Production Systems – quantify tree growth rates, harvestable yields etc.
- Catchment Management – quantify inputs (rainfall) and outputs (plant water use, drainage, runoff)
- Biodiversity Management – quantify tree health and stress to ensure a forest system will continue to grow for many generations.
- Science – Research and Climate change understanding and management.
In all instances the same or similar sensors will be used but with different deployment densities and measurement frequencies.
- Solar radiation – energy input to drive evapotranspiration
- PAR radiation – photosynthetic active radiation
- Wind Speed
- Wind Direction
- Rainfall (typically 0.2 mm tip)
- Rainfall variability can be large across a forest catchment. Rain gauges can now be spread spatially at low cost using LoRa wireless systems across the catchment.
Plant Growth and Plant Water Use:
- SFM1 – Sapflow – litres of water used per 10 minutes and per day continuously.
- PSY1 – Plant Water Potential (water stress) per 20 minutes continuously.
- DBV60 – Dendrometer – tree growth in circumference.
Soil Moisture and Soil Water Potential:
Soil moisture is typically measured in a profile of sensors at 6 to 8 depths. This gives an indication of plant water use, rooting depths, infiltration depths, hard layers and changes of rooting pattern over time. Sensors used are typically robust with lifetimes of 10 to 20 years whilst buried, such as the MP406.
- There are also lower priced capacitance sensors which are common in agriculture but these typically have a 2 to 3 year life time and as such have limited value in long term monitoring.
- Soil water potential is best measured with either ceramic, which has limited lifetime, or robust sensors and logging systems with soil water content/soil water potential curve characteristics of the soil being monitored for conversion.
- Spatial variability in soil moisture in surface soil moisture is often very large in forests. Soil moisture sensors can now be spread spatially at low cost using LoRa wireless systems. Typically these sensors would be buried at 30 cm depth for long term deployment and may be located near a rain gauge.
IOT and wireless systems create significant opportunities for forest management. IOT offers the possibility to make monitoring cost effective in forests not currently monitored and also to combine with a system using specialist tree instrumentation (SFM1, PSY1, DBV60) to develop spatial monitoring to complement the more localised intensive monitoring of a lesser number of representative trees.
The ICT Telemetry Hub has been developed as a Gateway for use in remote locations as in forests. It has both LoRa and RF capability for data collection and 3G, satellite etc transmission. It is low power (solar), environmentally rugged, and has long term data storage in CSV format.
ICT International has considerable experience globally setting up such systems in both forests and tree cropping systems in agriculture such as almonds, macadamia, sandalwood etc; Also botanic gardens, urban forests and street tree systems.
ICT International has been in the business of developing instrumentation, deploying these systems with customers (scientists and commercial forestry/agriculture) and assisting with data interpretation since 1982.