Searching for Bitter Orange Trees in Palermo

 An urban walk through select streets in the neighborhood of Palermo, starting at the intersection of Santa Fe Ave. and Scalabrini Ortiz Ave.

The idea behind the route was simple. I accessed the Urban Tree website (https://arboladourbano.com/) and applied a filter to locate registered bitter orange trees (Citrus aurantium) in the area. By eye, I selected a walking range of between 5 and 6 kilometers, mapping out a route that marked four points of interest.

The fruiting season for this species runs mainly from autumn through winter. Full ripening takes about eight months, at which point the fruits turn a deep orange hue and reach peak harvest condition. Being the month of July, the premise suggested that identifying the species would be straightforward thanks to the oranges hanging from the branches.

However, after completing the trek and closely inspecting all four selected points, I found only two standing specimens.

It is possible that I simply missed them or passed them by, but it is also likely that they are simply no longer there. Why would a tree registered on the map cease to exist on the sidewalk?

The absence of these specimens is usually due to the interaction between urban management dynamics and time lags in data updates. The main causes can be grouped into three categories:

1. Urban Vegetation Dynamics (Physical Factors)

•    Felling due to infrastructure or construction: It is common for trees to be removed during public works (sidewalk repairs, laying of cables or pipes) or private building developments.
•    Disease or risk of falling: Citrus aurantium is vulnerable to root fungi, pests, and hollow trunks. When facing a risk of falling or an advanced state of decay, the municipality proceeds with preventive removal.
•    Weather events: Storms with heavy wind gusts frequently blow down mature trees whose root systems were already compromised.
•    Unauthorized removal by property owners: Residents frequently remove trees out of inconvenience: fallen fruit soils the sidewalk and attracts insects, or the roots lift the pavement tiles.

2. Data Lag (Platform Factors)

•    Outdated census data: The map relies on the Official Tree Census of the City of Buenos Aires alongside crowd-sourced contributions. Because official censuses are updated years apart, trees removed in the interim remain visible on the platform.
•    Geolocation or initial identification errors: Uploaded locations can have error margins of several meters, appear on the opposite sidewalk, or stem from an initial census mistake that misidentified the species for another citrus tree.

3. Alterations in Appearance (Visual Factors)

•    Drastic pruning (topping): Recent severe pruning strips the tree of its characteristic canopy, leaving it looking like a dry pole and making visual identification impossible at first glance.
•    Replacement with young specimens: When the municipality removes a mature orange tree, it often plants a sapling of a different species (such as a jacaranda or a crepe myrtle). The tree pit remains occupied, but the target species is gone.

Urban hiking (Urban Trek), city-trekking, and low-intensity steady-state walking (LISS). An active yet essentially contemplative journey.

Link to Wikiloc: https://es.wikiloc.com/rutas-observacion-de-flora/walk-through-palermo-caba-in-search-of-bitter-orange-trees-279630292