Quercus pacifica Nixon & C.H.Mull.
Island Scrub Oak; Channel Island scrub oak; Pacific Oak
Cited as Kew's World Checklist cites it, Quercus pacifica Nixon & C.H.Mull.: GBIF's backbone key for this page carries the name with another author, Nixon & C.H.Müll.
80 photographs › At a glance
- Jan, shaded
- Feb, shaded
- Mar, shaded
- Apr
- May
- Jun, under 5 mm of rain
- Jul, under 5 mm of rain
- Aug, under 5 mm of rain
- Sep, under 5 mm of rain
- Oct
- Nov
- Dec, shaded
Summary
Quercus pacifica is a species of oak known by the common names island scrub oak, Channel Island scrub oak, and Pacific oak.
Quoted from Wikipedia, "Quercus pacifica", CC BY-SA 4.0.
Cultivation
Seasons
The rain rule reads a winter growing season: 70% of the median year's rain (374 mm of 475 mm) falls in December to March, cooler than the year (wet-season mean 13.2 °C against a yearly mean of 15.0 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: June to September.
Rain
475 mm in the median year at the habitat, 374 mm of it December to March. Wettest month January at 109 mm, driest months (2 at 1 mm); 4 months under 5 mm. Across the grid cells of the range the year's total runs 322 mm to 580 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 470 mm, is the year's rain at the top of the page; the 475 mm here is the median year's, the twelve monthly medians added, which the rain rule reads. Habitat calendar, northern hemisphere; median year across the grid cells of the range, CHELSA.
Light
Open sky over the habitat: 19 to 52 mol/m²/day across the year (daily light integral, median year across the grid cells of the range, CHELSA; the lowest 10th-percentile month across the cells is 18, the highest 90th-percentile month 52).
Warmth and air
Monthly means: the coldest month's mean nightly low 12.2 °C in February (across the grid cells of the range 11.4 °C to 12.7 °C), the warmest month's mean daily high 18.3 °C in August (median year across the grid cells of the range, CHELSA). Cold floor: none read. The nearest figure is 12.2 °C, the coldest month's mean nightly low, February, in the median year (CHELSA); a month's mean of its nightly lows is warmer than the nights a floor is read from. The daily extremes were read at a weather cell that is mostly sea and are not used.
Relative humidity at the habitat: 56 to 72% across the year (monthly means, median year across the grid cells of the range, CHELSA). A figure about the air, saying nothing about how the plant takes water.
How this section is made
Each card states this species' habitat figures with their sources, and what two fixed rules read from them; nothing here says what the plant does, wants or tolerates. The rules · the terms.
Seasons. Read from the median year of CHELSA monthly rainfall and mean temperature across the grid cells of the range: the rain rule takes the smallest set of months carrying 70% of the rain and calls it winter when its mean is more than half a degree below the year's, summer when more than that above, and neither in between; the temperature rule, used only under 120 mm, names the cooler six months when they are at least a degree cooler than the other six. Months are shifted for the other hemisphere only where the temperature curve moves 4 °C or more and the habitat lies 10° or more from the equator. A reading of the curves, not an observation of the plant.
Rain. CHELSA monthly precipitation, median year across the grid cells of the range. The rain that falls where the species is recorded; nothing about how the plant takes water.
Light. CHELSA shortwave radiation at each envelope cell, a daily-mean flux taken to a daily total and converted at 2.07 mol of PAR per MJ. The sky over the habitat, measured; what reaches a plant under a rock, a shrub or a shade cloth is not.
Temperature. CHELSA monthly means, median year across the grid cells of the range. No cold floor is read without a daily extremes series; the coldest month's mean nightly low named in its sentence is not one. Not a measured survival limit for any plant in a pot.
Humidity. CHELSA relative humidity, median year across the grid cells of the range.
Climate across the habitat
Habitat months, northern hemisphere
Mean daily high from 14 °C in Jan, Feb, Mar, Apr and Dec to 18 °C in Jul, Aug, Sep and Oct; mean nightly low from 12 °C in Jan, Feb and Mar to 17 °C in Aug and Sep. The cold quarter, Jan to Mar, is the three months around the coldest month's mean nightly low, centred on the 3 months in a row that tie for it. 475 mm of rain in the median year (the twelve monthly medians added), the wettest month Jan. The bands show the 10th to 90th percentile across 37 habitat cells. Beneath: daily light integral and relative humidity through the year, each on its own scale.
Figures by month
| Figure | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Day °C | 14 / 13–15 | 14 / 13–14 | 14 / 13–14 | 14 / 13–15 | 15 / 14–16 | 16 / 15–17 | 18 / 16–19 | 18 / 17–19 | 18 / 17–19 | 18 / 17–18 | 16 / 15–17 | 14 / 13–15 |
| Night °C | 12 / 12–13 | 12 / 11–13 | 12 / 11–13 | 13 / 11–14 | 13 / 13–15 | 15 / 14–16 | 16 / 15–18 | 17 / 16–18 | 17 / 16–18 | 16 / 15–17 | 15 / 14–15 | 13 / 12–13 |
| Rain mm | 109 / 68–132 | 108 / 74–139 | 75 / 51–92 | 29 / 18–34 | 8 / 5–10 | 2 / 1–2 | 1 / 0–1 | 1 / 1–2 | 4 / 4–5 | 16 / 13–21 | 40 / 29–51 | 82 / 53–92 |
| DLI | 21 / 20–22 | 26 / 25–27 | 36 / 35–37 | 45 / 44–45 | 50 / 49–50 | 52 / 51–52 | 50 / 50–51 | 47 / 47–47 | 39 / 39–41 | 31 / 30–32 | 23 / 22–25 | 19 / 18–20 |
| RH % | 56 / 53–59 | 58 / 56–61 | 61 / 57–64 | 62 / 56–66 | 67 / 60–71 | 70 / 61–78 | 72 / 60–87 | 71 / 57–87 | 68 / 57–79 | 61 / 55–67 | 56 / 53–60 | 56 / 52–58 |
The daily extremes were read at a NASA POWER cell that is 12% land: neither it nor the next candidates whose coldest month's mean nightly low is within 2 °C of the median across cells sit in a POWER cell that is mostly land, and the rule reads a cold floor only from a cell that is mostly land, so none is read for this species. Nor is the coldest month's mean nightly low taken as one: it is a mean of a month's lows, not its coldest night. What that cell gave over 44 years: absolute minimum 4.6 °C, 1st-percentile night 8.7 °C, 99th-percentile day 27.2 °C.
How this section is made
Natural habitat
How this section is made
Photographs
Photographs: (c) Devon Bradley, some rights reserved (CC BY); author not stated, no rights reserved · CC0 (3); (c) mel letterman, some rights reserved (CC BY) (2).
Related
Similar habitat climate The 6 nearest by mean daily high, mean nightly low and rain, month by month. How.
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Quercus acerifolia Fagaceae Photo: CC BY, Laurel Meredyk
Quercus acuta Red-wood evergreen oak Photo: CC BY, Marco Mussita
Quercus × acutidens Fagaceae Photo: CC BY, Eric Alan Isaacson
Quercus acutifolia Fagaceae Photo: CC BY, Neptalí Ramírez Marcial
Quercus acutissima Sawtooth oak Photo: CC BY, Will Burnside
Quercus afares African Oak Photo: CC BY, Mehdi Chetibi
Quercus affinis Fagaceae Photo: CC BY, Neptalí Ramírez Marcial
Quercus agrifolia Coast live oak Photo: CC BY, Gregory Wada
Quercus alba White oak Photo: CC BY, Jeff Clark
Quercus aliena Oriental white oak Photo: CC BY, plant 0302
Quercus alnifolia Golden Oak Photo: CC BY, Aurelijus Narbutas Quercus × andegavensis Fagaceae all 221 ›Names & registers
Also known as Quercus dumosa var. polycarpa. (GBIF Backbone)
The record
Every figure here is derived from public data by a stated rule and names its source; nothing about this species is written for its page by a person or by AI, apart from the marked, credited quotations. How →
Where this page came from built 2026-10-22
gbif.species answeredasked 2026-10-22GBIF's key 2881701 is Quercus pacifica Nixon & C.H.Müll.; the page links Kew's Quercus pacifica Nixon & C.H.Mull., and the name is cited as Kew cites itgbif.synonyms answeredasked 2026-10-22gbif.vernacular answeredasked 2026-10-22names fetched 2026-10-22wcvp.distribution answeredas of 2026-06-04gbif.occurrences answeredas of 2026-10-21GBIF occurrence download https://doi.org/10.15468/dl.hbdw64, of 2026-10-21; 42 records within 1 km of a botanic garden, herbarium or zoo left out (42 at a botanic garden or arboretum; Wikidata's list)climate answeredasked 2026-10-22climate.extremes answeredasked 2026-10-22NASA POWER (MERRA-2) daily 1981–2024, cell 34.00_-119.375, lapse-corrected +160 m at 6.5 °C/km; read, and set aside: NASA POWER's cell is mostly sea (12% land), so no cold floor is shownwikidata answeredasked 2026-10-22wikipedia answeredasked 2026-10-22inat.photos.wild answeredasked 2026-10-22from iNaturalist's open data of 2026-09-27: research-grade observations with an open-licence photograph, the 24 whose photographs iNaturalist received last (the open data holds no votes); filled 2026-10-22inat.photos.cultivated not askedgbif.media answeredasked 2026-10-22openalex not askednot yet asked for this reference; a later fill takes the papers from OpenAlex's snapshotEvery source is recorded as having answered, reported nothing, refused, failed, not been asked, or answered twice where one answer is taken (“not taken: two items answered”), and, for a source asked when this page was built, when: the figures are as the source held them that day; a source read from a file (Kew's World Checklist, a GBIF download) says "as of" the file's day instead; a row carried from an earlier build of the page names that build instead. Only “nothing to report” is ever shown as an absence. Records came from 19 datasets via GBIF.org; each carries its own licence.