Nut tree mapping with iNaturalist

Trees offer an abundance of gifts. Both wild and tended trees provide food, fuel, fiber, animal feed, medicines, and a range of co-benefits, including clean water and wellness. Much more has been said on this, and there is more to say. For now, I zoom in.

How can we reconnect with trees for basic needs? One way I’m drawn to is that of a sprouting organization called the Keystone Tree Crop Cooperative (KTCC). KTCC aims to gather food from existing nut trees and enable broader audiences to connect with these gifts from trees.

To catalyze the harvest of existing nut trees, gatherers will benefit from incentives (such as compensation for nuts), education on methods (including food quality standards and comfortable tools), and guidance on gathering locations (as in maps). This post is about the latter: mapping existing nut trees and identifying hotspots to efficiently harvest from, with an eye for the coming autumn 2021.

iNaturalist was homed in on as a pretty good platform for nut tree info. There are observations and observers already on iNaturalist. This site also has experts maintaining a cross-platform database of trees, which is useful to build on. While iNaturalist has some limitations discussed below, it is a good starting point – let’s take a look!


I love hazelnuts (Corylus spp) and would like to rally friends to engage these beings. I understand both wild and cultivated hazels are found in my region, but not knowing where exactly, I would spend a lot of time searching that I could spend gathering. iNaturalist offers a starting point in the search.

How to lookup nut trees with iNaturalist in 5 steps

1. Start at https://www.inaturalist.org/ and find its search bar or ‘Explore’ page.

2. Enter the genus or species name in the search bar.

iNaturalist search field with genus entered

3. Click the ‘Filters’ option and update your filters. Viewing only Research Grade IDs will reduce false positives and ensure the observations are of wild trees, more likely to be forage-friendly. More about the Research Grade ID filter below in the section on limitations.

iNaturalist search filters with Research Grade toggled on

4. Navigate to your location of interest by zooming or entering the location, to get a finer scale view of observations and to get some stats. 1

iNaturalist search results zoomed in on southeast PA for observations of Corylus spp.

5. Click the map markers to pull up a message window with the observation summary, then when you find a promising observation, click the species name to view the full observation page.2 On the observation page, you can get a closer zoom and see the radius that the observer estimated for the location.

iNaturalist observation page for an American hazelnut in French Creek State Gamelands

Bringing it all in

At this point, you can view the crowd-sourced observations for genus or species you want to gather from, anywhere in the world. You can assess individual observations to get more info and decide if a spot is worth further investigation. Now, it’s a matter of exploring! You can go and check out the location, verify the ID, and take steps to make harvests happen!

Some limitations

iNaturalist on its own doesn’t do a great job prioritizing locations to harvest, it just indicates where some tree of interest have been seen. More specifically:

  • Viewing Research Grade IDs in iNaturalist means observations marked ‘cultivated’ will not be included. Cultivated trees are probably best connected with through different paths than iNaturalist anyway. Local focus groups like the Pennsylvania Nut Growers Association offer networking opportunities with tree crop cultivators.
  • The crowd-sourced IDs do not provide much guidance on the nature of each tree, only that there is a tree there. Even if an observer does add more notes, it is not easy to navigate those notes in bulk. As a result, this method shows us where some trees are, but it makes it difficult to prioritize locations for harvest.

Next steps

As noted in this post’s intro, the KTCC approach will involve incentives, education on methods, and guidance on locations. This post explores a little about locations. Follow KTCC for updates on the other fronts.

To improve location guidance and address some of iNaturalist’s limitations, custom Observation Fields could be added to provide more useful info for KTCC cooperators. (‘Tree crops‘ is already a custom field which could be reused for this effort, originally setup in 2014 for a project in New Zealand!) When a custom field is added by one user, it becomes available for other users to enter in their observations, and those custom fields can filter whether or not an observation is included in an iNaturalist collection. These custom fields can also be exported as attributes of observations, for inclusion in spatial analysis.

Here are examples of custom fields (and potential responses) that could be entered with nut tree observations:

  • What frequency of this species can be expected in this area? (one | few | many scattered | many clustered)
  • What quality crop can be expected? (abundant | moderate | uknown)
  • Any notable physical features of the crop? (user-defined string, e.g. “thin shell, delicious taste, small nuts”)
  • When does this crop tend to be ready for harvest? (early sept | mid sept | late sept | early oct | etc.)
  • How accessible is this tree from a car? (roadside | <5 minute walk | 5-15 minute walk | >15 minute walk)
iNaturalist window for adding custom observation fields
Window for adding custom observation fields in iNaturalist.

As noted, iNaturalist works well with spatial analyst tools, and this enables us to answer questions about the spatial relationships of data in iNaturalist. Where are nut trees within 60 miles of me? Where are clusters of abundant producing Carya spp specimen? If we had custom fields, we could filter and map trees based on known quality producers.

For now, I leave you with a question and with a screenshot of QGIS showing spring 2021 hazelnut hotspots, highlighted on a map of all trees in the iNaturalist Keystone Tree Crops project (which is currently a simple collection of desired nut trees observed in PA):

QGIS screenshot showing iNaturalist results from Keystone Tree Crops Cooperative, with hazelnut species marked with points and hotspots.

What needs or suggestions do you have for location guidance on nut harvesting? Please share your constructive ideas and feedback below! Thank you for your interest.

  1. In iNaturalist search results, the count of observations and species is information that could guide your gathering search. You can fine-tune those numbers by entering a specific location (such as a state or county) or by zooming to the area of interest and clicking the orange ‘Redo search in map’ button.
  2. You can use your browser’s ‘back’ button to return to the search map.

What do you think?