Scientific name: Eucalyptus deglupta

POWO Status: Tree

IUCN Red List threat level: Vulnerable

GPS Location: 17° 42′ 53.99″ N, 64° 49′ 51.58″ W

Observations:

Phenological Markers – Rainbow Eucalyptus (Eucalyptus deglupta)

1. Leaf Behavior
Rainbow Eucalyptus is evergreen, retaining its leaves year-round in tropical climates like St. Croix.

• Leaves are long, lance-shaped, and arranged alternately along smooth, rounded branches.
• While individual leaves may yellow and fall periodically, there is no synchronized leaf drop.
• New leaf growth can occur intermittently, especially after rain or pruning.

Observation Tips:

• Track new leaf flushes, which may appear slightly lighter green.
• Minimal seasonal leaf variation makes bark observation more useful than foliage for phenology.

2. Bark Shedding (Key Visual Marker)
The most notable phenological trait of this species is its regular exfoliation of bark.

• Outer bark peels away in thin, papery strips, revealing underlying layers in bright green, blue, purple, orange, and maroon.
• Bark shedding occurs continuously but unevenly, resulting in a mosaic of shifting colors.
• Rainfall and tree vigor influence the rate and extent of shedding.

Observation Tips:

• Track timing and location of bark peeling—some trunks may peel more heavily at certain times.
• Photograph color transitions and patch patterns, especially after rains.

3. Flowering
Small, creamy-white flowers appear in clusters (umbels) and are rich in nectar.

• Flowering may occur sporadically year-round, but in St. Croix may show peaks during wetter months (May–October).
• Flowers are less conspicuous than other features, often hidden among foliage.

Observation Tips:

• Look for flower buds and pollinator activity, especially bees.
• Monitor clusters along upper branches, especially after extended rains.

4. Fruiting
The tree produces woody capsule fruits, each containing numerous tiny seeds.

• Capsules mature several months after flowering, turning from green to brown.
• Seeds are wind-dispersed, and fruiting can overlap with new flower cycles.

Observation Tips:

• Record formation and drying of seed capsules.
• Note seed fall timing and appearance of capsule remnants under the tree.

5. Seasonal Pattern (St. Croix)

• Year-round: Bark shedding and leaf retention
• May–Oct (wet season): Increased flowering, fruiting, and new growth
• Dry season (Jan–Mar): Slower activity, possible peak in bark color contrast