DOI: 10.5281/zenodo.15653340
title: UruDendro4: A Benchmark Dataset for Automatic Tree-Ring Detection in Cross-Section Images of Pinus taeda L.

description: If you use this dataset please cite the UruDendro4 manuscript.

Method

Image and annotations can be inspected using the TRAS tool developed during the project.  

1) Open TRAS

2) Open Image

3) File>Load Annotations

 

Harvest Site

A total of 102 cross-sections of the species P. taeda were collected from the site known as "La Altura", located approximately 4 km from the city of Tranqueras (31°13'30.2'' S, 55°46'53.6'' W), Department of Rivera, Uruguay. Trees were felled using a chainsaw, and four discs per stem were extracted at heights of 0m, 3m, 6m, and 9m. An additional disc was collected at 1.3m for the T0 treatment. The samples were harvested in 2024, and the specific harvest months are detailed in Table 1. Silvicultural treatments are described in Table 2.

 




Treatment
Harvest Date


T0
B1, B2 and B3  second week of July


T2
Last week of April


T4
B1 and B2 last week of April; B3 first week of June


T6
B1 and B3 first week of June; B2 second week of May




Table 1 Harvest datest for each treatment and block

 




Treatment
Thinning timing [years]
Pre-thinning density [trees.ha^{-1}]
Post-thinning density [trees.ha^{-1}]
Pruning height [m]
Current density [trees.ha^{-1}]


T0 – Commercial management
11
600
350
between 5.5 and 8.0
350


T2 – Heavy thinning / High pruning
8
600
250
8.0
250


T4 – Current thinning / High pruning
8
600
350
8.0
350


T6 – Two thinnings / High pruning


1st thinning: 8

2nd thinning: 18

600


1st thinning: 400

2nd thinning: 200

8.0
200




Table 2 Description of silvicultural treatments: thinning schedule, tree densities before and after thinning, pruning height, and current stand density.

The soils in the area are very deep, with limited drainage, loamy-sandy in texture, and extremely low fertility, having a productivity index of 53. The dominant soils are Umbric Albic Luvisols. These are classified as priority forestry soils and belong to the CONEAT group 7.42. The terrain consists of gently rolling hills with slopes of up to 3%.

Image Acquisition

The discs were polished using an electric planer. In addition, T0 samples were also sanded using an electric belt sander. At the time of image capture, the discs were moistened. Photographs were taken under varying lighting conditions: samples from T2 and T4 (B1 and B2) were photographed indoors under artificial white light; T6 (B2) samples were photographed outdoors; T4 (B3), T6 (B1 and B3), and T0 samples were photographed outdoors in shaded conditions. All photographs were taken using an iPhone 15 Pro. The minimum image width is 1317 pixels, and the maximum width is 4695 pixels. 

Sample codes follow the structure:

TX_BY_NZ_W

 

Where TX indicates the treatment applied to the tree (0, 2, 4, or 6); BY refers to the block (1, 2, or 3);  NZ refers to the tree identifier (e.g., 3, 12, 23, etc.); and W refers to the sample height (A = between 10~30 cm, B = 3m, C = 6m, D = 9m, and ADAP = 1.3m).

Annotation Details

The software tool used to generate the annotations was Labelme , which produces closed polygons defined by a set of vertices. 
description: File structure

In general, the file structure for each collection goes as follows:



images/ - Folder with the image samples

images_no_background/ - Folder with the images after the background has been removed

annotations/– annual_rings/ - Annual ring annotations

pith_location.txt - file with the pith pixel location for each image


Where each sample has a unique code. For example, sample T4_B3_N1_C has five different files:



images/T4_B3_N1_C.png

images_no_background/T4_B3_N1_C.jpg

annotations/annual_rings/T4_B3_N1_C.json