i-Tree Research Suite

Research Suite Overview


The i-Tree Research Suite offers peer-reviewed models to analyze the benefits of trees and other landscape attributes and assist in forest advocacy and ecosystem health. Below is a list of tools that are currently available. If you have questions about any of these tools, please contact i-Tree Support <info@itreetools.org>. Note that free technical support is not available for the research suite, but expert consultation can be arranged by reaching out to the i-Tree Team.

Visit the Core Tools listing for more user-friendly tools that make ecosystem services science accessible to broad audiences. Use of the i-Tree Research Suite code indicates acceptance of the EULA.

Introductory Materials

Research Suite Downloads & Tools

Downloads for HydroPlus and supporting tools are listed below. Note that the Research Suite exists in a technical and academic environment. Updated science and bug fixes are continually being implemented.


  • i-Tree HydroPlus (revision 1267 .zip) including model .exe, manual, test cases, auto-testing script, and PEST calibration (zip): a unified C++ codebase for various environmental models that share common algorithms. HydroPlus models include:
    • i-Tree Hydro: a statistically-distributed hydrology model simulating the effects of land cover changes on water quantity and quality, unique in explicitly modeling vegetation processes (Wang et al., 2008).
      • Green Infrastructure: Addition to i-Tree Hydro which simulates and measures the benefits of green infrastructure installations.
    • i-Tree Cool Air: a spatially-explicit air temperature model simulating the effects of land cover changes using i-Tree Hydro's water budget and an energy budget that explicitly accounts for vegetation processes (Yang et al., 2013).
    • i-Tree Cool River: a river temperature model for simulating the effects of channel morphology, riparian shading, tributaries, stormwater inflow, groundwater mixing, and river restoration by using a set of 1D advection, dispersion, and energy flux equations (Abdi & Endreny, 2019).
  • WeatherPrep weather preprocessor (revision 167 .zip): a weather pre-processor required to create weather inputs for i-Tree HydroPlus (Hirabayashi & Endreny, 2016).

  • i-Tree Energy: a building energy balance model coded in Python, mechanistically simulating the heating and cooling energy savings benefits for buildings with nearby trees (DeMarco & Endreny, forthcoming).
  • i-Tree Buffer: a nutrient hotspot mapping tool coded in Python, based on a contributing area dispersal area (CADA) nonpoint-source (NPS) water quality model (Stephan & Endreny, 2016). i-Tree Buffer will be integrated with HydroPlus in 2023.
  • Tree Compensation Calculator: data tables and a calculator to estimate the number of trees (or monetary value) needed to compensate for the loss of a healthy tree of any size (Nowak & Aevermann, 2019).
  • Autocalibration utilities for HydroPlus (revision 2) derived from PEST 17.1 (.zip)