Tree Caliper and Counter

Manually measuring tree caliper and counting trees in high density ornamental, fruit and nut tree nurseries are time-consuming and expensive tasks. The goal of the CASC researchers, engineers and Extension faculty is to increase production efficiency and assist nursery producers in projecting inventory with mobile devices that do both tasks automatically

COUNTER

In cooperation with stakeholders, we have developed an on-the-go tree counter to assist in effective, accurate inventory management of high-density nurseries that supply ornamental, nut and fruit trees for out planting in the landscape or orchards.  The counter remotely counts trees using pulsed laser light 7” - 12” from the stem displaying and recording the count as it passes the tree.  Currently a tablet is utilized as the graphic user interface allowing the grower to input needed details of the operation and set operating parameters that include minimum caliper and tree spacing. During operation, the device is attached to commonly-used nursery equipment such as tractors or ATVs, and has a suggested operating speed of 2 - 4 mph.  The travel speed and route of the equipment is recorded using a low-cost GPS.  The counter system (counter, tablet computer, and GPS) has been tested when mounted to tractors and ATVs at speeds from 2 to 10 mph. It is being evaluated for commercialization at commercial nurseries in the Western United States (CA, OR, WA).  On-farm evaluations have resulted in 96 to 99% accuracy of counting ornamental and fruit trees with a caliper of 1/8” and greater that are spaced a minimum of 9” apart.

CALIPER

An on-the-go caliper device is currently under development by CASC team members to remotely measure and record the caliper of unstaked bare-root trees at the time of harvest. In addition, the device can be used to measure the caliper of unstaked or unobstructed trees in an orchard or nursery setting.  The device is mounted to the front of a digger at a height of 6” or greater to assist in estimating the quantity of trees per saleable grade based on caliper (± 3 mm).  The target working travel speed of the on-the-go caliper is 1 to 4 mph. The device works by recording multiple images of the tree trunk through a filtered camera that sees only two parallel laser lines projected on the stem of the tree.  The collective images are processed in real-time and average caliper is recorded.  The on-the-go caliper device is managed by the operator through a rugged tablet or computer.  The graphic user interface, developed in cooperation with stakeholders, allows for the user to record farm specific data and manage operating parameters such as estimated caliper and tree spacing.  In addition, all data is georeferenced allowing the user to view the data spatially and make inferences on the impact of field conditions or cultural practices on crop growth.  Initial on-farm evaluations in Oregon have accurately measured and recorded the caliper of ornamental trees ¼” or greater.  Work continues on the on-the-go caliper device to increase precision and ensure safety for users.