Secondary Amazon rainforest partially recovers tree cavities suitable for nesting birds in 18–34 years

Passive restoration of secondary forests can partially offset loss of biodiversity following tropical deforestation. Tree cavities, an essential resource for cavity-nesting birds, are usually associated with old forest. We investigated the restoration time for tree cavities suitable for cavity-nesting birds in secondary forest at the Biological Dynamics of Forest Fragments Project (BDFFP) in central Amazonian Brazil. We hypothesized that cavity abundance would increase with forest age, but more rapidly in areas exposed to cutting only, compared to areas where forest was cut and burned. We also hypothesized that cavities would be lower, smaller, and less variable in secondary forest than in old-growth forest, which at the BDFFP is part of a vast lowland forest with no recent history of human disturbance. We used pole-mounted cameras and tree-climbing to survey cavities in 39 plots (each 200 × 40 m) across old-growth forests and 11–34 year-old secondary forests. We used generalized linear..., We surveyed tree cavities in upland Terra Firme forest at the Biological Dynamics of Forest Fragments Project (BDFFP), north of Manaus in central Amazonas, Brazil (02°20'S, 60°5'W). 
At the time of our study, the area comprised a mosaic of old-growth forest, grasslands, and regenerating forest of different ages. Within this mosaic, we placed 39 plots: 8 in old-growth forest and 31 in secondary forest aged 11–34 years. Each plot measured 200 x 40 m (0.8 ha). For each stand age, we aimed to balance the number of plots in secondary forest that grew after cutting only vs. cutting and burning, but this was not always possible. Plots were centered along established linear transects or mist-net lines from other projects, with 200 m length and 20 m extension to each side. We spaced plots as well as was feasible given the existing trail network, which was limited, especially in secondary forest.
From July to October 2013, two observers searched for cavities by examining each tree within each plo..., , # Secondary Amazon rainforest partially recovers tree cavities suitable for nesting birds in 18–34 years

The dataset contains numbers of cavities and their measurements from 39 forest plots (each 200 x 40 m in size) at the Biological Dynamics of Forest Fragments Project north of Manaus, Brazil, as well as code to produce the analyses in Dantas Oliveira et al. 2024.

## Description of the data and file structure

Dataset 1: Secundaria.csv. Dataset of the Plot ID (IDTransecto), Reserve (Reserva), forest age (Idade), fire history (Fogo; 0 = unburned, 1 = burned), UTM coordinates, and number of cavities for each of the 31 0.8-ha plots in secondary forest.

Dataset 2: Primario.csv. Dataset of the Plot ID (IDTransecto), Reserve (Reserva), forest age (Idade), UTM coordinates, and number of cavities for each of the 8 0.8-ha plots in old-growth forest. forest age (Idade) is 100 by default for all old-growth forest (where age is certainly >100 years).

Dataset 3: CRT.csv. Dataset of measure...