One of the things we don't emphasize enough at the Garden is the fact that we neighbour Pacific Spirit Regional Park. The cliffside forest to the west of the David C. Lam Asian Garden, the Garden's entrance and our parking lot provides biodiverse frames for our views of Georgia Strait and the distant Gulf Islands. This photograph, from our parking lot, shows what can happen (oh so very rarely) when one encounters a combination of late afternoon autumn light and a retreating (or advancing) fogbank directly above where the open water meets the cliff.

Ecological processes are difficult (for me) to photograph, but I do think this image at least partially illustrates the effect of vegetation on light attentuation--where the foliage is thickest, most of the light is absorbed or reflected. Thin or no foliage, of course, permits light to pass through. Figure 1 in Schäfer, K. V.R. & Dirk, V. W. (2011) The Physical Environment Within Forests. Nature Education Knowledge 2(12):5 shows how the intensity of light reaching the forest floor and lower levels of the forest declines with canopy height in an oak forest in the summertime.

The variable amount of light reaching the forest floor in different seasons can prompt niche differentiation, defined on Wikipedia as "the process by which natural selection drives competing species into different patterns of resource use or different niches". As an example, the floor of eastern North American hardwood forests, where one finds species such as Trillium grandiflorum flowering in the early spring, has a number of early spring-adapted plant species that complete growth and flowering before the leaves fully emerge on the canopy trees. The forest floor species that occupy the same physical space but instead grow and develop during the summer have to deal with the low intensity of light and generally drier soil conditions (but, conversely, do not have to be adapted for potential early spring conditions such as harsh frosts or snow). Occupying (potentially competing for) the same space but adapted to conditions associated with different times, spring- and summer- flowering species can be considered to niche differentiated.

Evergreen forests, like the second-growth forest of Pacific Spirit Regional Park, do not have the same springtime phenomenon. However, one can still observe the effects of light attenuation by paying close attention to the changes in species composition as one transits from the edge of the forest to the core (as one might also observe in forests bordering clearcuts, or riverbanks in the tropics). High light levels at the forest edge generally promote an elevated diversity of shrubs and herbaceous plants, whereas the forest core tends to have fewer of these types. Do note that it is not necessarily an elevated diversity of native species, as invasives tend to be better competitors in these edge sites (at least early on).

I had promised to share photograph details from time to time. This image is actually 3 photographs composited together, using a technique known as tone mapping, which "addresses the problem of strong contrast reduction from the scene radiance to the displayable range while preserving the image details and color appearance important to appreciate the original scene content". In other words, it is a high dynamic range, or HDR, image. The three photographs were exposure bracketed, so one underexposed, one was overexposed, and one was somewhere in the middle. These were then combined in software that algorithmically composites the three into a single image, essentially drawing from the highlights of the underexposed image (so that the photo is not entirely blown out), the shadows of the overexposed image (to preserve detail in the shadows) and pulling both of these closer to the middle exposure of the photo. I'm oversimplifying, but that's the gist of it.

HDR images have a poor reputation among many in the digital image world, with the critique that most applications of the technique exceed the boundaries of believability. If done subtly, though, the tool is useful for overcoming the limitations of a single exposure on a camera while still preserving what was seen by the photographer. I hope that today's photograph falls into the believable group, but feel free to disagree.

During Monday's class with the students in the Horticulture Training Program, we visited the Nitobe Memorial Garden. Although I primarily teach the introductory plant sciences course, I also find the time to explain the history of the Garden and its components. Today's photographs are both cropped versions from the same source image, which was composed quickly and taken handheld after the tour was completed.

Acer palmatum, or Japanese maple, is native to both Japan and South Korea. The plant in today's photograph is possibly a cultivar, but if it is, that information has been seemingly lost sometime during the past five decades. Like many Japanese species, it was first described and published scientifically by Carl Peter Thunberg, a Swedish botanist who visited Japan for a span of 14 months in 1775-1776. It should be noted that Thunberg didn't have the luxury of traveling the countryside to botanize (due to restrictions on movements of foreigners in Japan), so his collections were limited to areas that typically had some measure of cultivation. Indeed, he published many species with the specific epithet japonica, though they were actually of Chinese origin and introduced in Japan. A search on the International Plant Names Index shows over 4700 records of species named by Thunberg, but there is some duplication of names; perhaps the true number is around 2000.

Read more about Japanese maples in gardening situations via the Royal Horticultural Society: Acer palmatum, a factsheet from North Carolina State University: Acer palmatum, and Missouri Botanical Garden: Acer palmatum.

Botany resource link: in case there isn't a BPotD entry published tomorrow for Hallowe'en, Spooky Orchids via the North American Orchid Conservation Center displays thirteen North American native orchid species with an accompanying blurb.

Bryant is the author of today's entry. He writes:

A big thanks to stevieiriswattii!@Flickr for today's images of Aesculus parviflora (image 1 | image 2 | via the Botany Photo of the Day Flickr Pool).

Commonly known as bottlebrush buckeye, Aesculus parviflora is a member of the Sapindaceae (and formerly placed in the Hippocastanaceae). The species is native to the southeastern United States (Alabama, Georgia, South Carolina and Florida). This deciduous shrub can range from 2.5-3.5m (8-12ft.) tall and 2.5-4.5m (8-15ft.) across, and typically reaches full bloom in the early to mid summer in its native range.

This species is has been declared a Plant of Merit by the Missouri Botanical Garden for its explosively showy inflorescence and intriguing palmate foliage, which can turn a bright golden yellow in the fall.

This photograph is from two autumns ago, when it was a later-than-usual year for autumn colours in eastern North America. Fortunately, one small stretch of Highway 215 near the New Brunswick-Québec border was nearing peak in late September, though I only discovered it on my last day in the area. It's not really a "Natural Landscape" (how I've categorized it), as the shrubs and herbaceous plants in the foreground are trimmed low from time to time (they are along the roadside). It's not really an intentional cultivated landscape, though.

This image from last autumn (late October) was taken in the E.H. Lohbrunner Alpine Garden here at UBC. Since no cultivar name is specifically assigned for this plant, it suggests that it is either an unidentified cultivated variety or grown as a seedling (and therefore would not be the same as its parent, even if its parent was a named cultivar). The peculiar notation, "[Dissectum Viride Group]", adds some information, indicating that this plant belongs to a Group of dissected-leaf Japanese maples from cultivation.

Missouri Botanical Garden has a gardening factsheet available: Acer palmatum var. dissectum [Dissectum Viride Group].

I used a different piece of software for processing this photograph--a program that merges two (or more) photographs taken at different planes of focus. It looks like I'll have to play with some of the settings, as the photograph appears a bit too saturated.

The intense low sun of a late autumn afternoon in combination with a breeze off the Salish Sea helped to produce this image a couple days ago in the David C. Lam Asian Garden.

While taking the photograph, I was only reacting to the sights and experiences of bright leaves and moving branches. In the back of my mind, I would have had some familiarity with similar techniques or approaches used by other photographers under the same conditions. However, thinking about the photograph a bit more, it could also complement a number of stories about the David C. Lam Asian Garden:

• - the combination of coastal woodland plants (represented by the Douglas-fir) and cultivated plants of Asian origin (the Japanese maples in the background)
• - along the same lines, one could also interpret that the solidity of the Douglas-fir represents what was here and what will be here in this place (it is timeless), whereas the maples are fleeting and less solid, less permanent
• - the maples remind of flames, an allusion to the fire that threatened the Asian Garden earlier this year
• - the charred scars of stumps and trunks of the few remaining original-growth native trees in the Asian Garden speak to the burning of the site in the early 20th century after it had been effectively clearcut -- had colour film existed then, it is not difficult to imagine a similar photograph being taken a century ago, but with real flames

A photograph from early this morning in the E.H. Lohbrunner Alpine Garden here at UBC. I'm making a bit of an effort to photograph anything red in relation to plants at the moment. This is in preparation for an early December presentation I'll be giving entitled "Red Reverie", in which I'll be discussing the colour red in plants, on topics ranging from food plant pigments to leaf colours, from attracting pollinators to preventing herbivory. Busy again today with meetings, but thought I'd sneak in a quick image for BPotD. For local readers of BPotD, autumn colours will continue to persist through this weekend, particularly in the Alpine Garden and the Carolinian Forest.

Today's photograph and written entry is courtesy of Anthony (Tony) Aiello, the Gayle E. Maloney Director of Horticulture and Curator at the Morris Arboretum of the University of Pennsylvania. I've had the pleasure of meeting Tony a couple times over the past decade during meetings of the North American China Plant Exploration Consortium. Much appreciated!

Tony writes:

This photo of Acer henryi (Henry maple) was taken recently at Niu Bei Liang Nature Reserve, in the Qin Ling mountains of Shaanxi Province, China. This was a remarkable location, in which we saw nine species of maple, and the identity of one of these is a mystery. The Acer henryi were growing in scattered places throughout the forest, often in clearings, and were showing early signs of this outstanding fall color. Unfortunately, we did not find any seed to collect. The other maples seen in this area were: Acer cappadocicum subsp. sinicum, Acer ceriferum, Acer davidii, Acer erianthum, Acer oliverianum, Acer pectinatum subsp. maximowiczii, Acer shenkanense (Acer tricaudatum), and the unknown species.

Acer henryi is found in botanic gardens but otherwise is not widely grown as an ornamental in North America. It is a handsome tree, with very clean summer foliage and outstanding fall color, ranging from deep purples to brilliant reds. As a result it merits more attention and would make an excellent small landscape plant.

Daniel adds: Acer henryi also has a lengthy chain of winged fruits, which provide additional interest. The species is named after Irish plantsman Augustine Henry, the first person of European descent to encounter and collect it.

Lastly, as an aside to local readers, the VanDusen Cedar Lecture Series hosts Ron Long speaking on a topic of great interest to me tonight, "The Unique Plants of Southern Oregon".

The Garden's Curator of Collections, Douglas Justice, took today's Botany Photo of the Day. He wrote the accompanying entry as well.

Koelreuteria paniculata, or golden rain tree, is a drought resistant tree from China, grown for its abundant summer flowers and its papery, lantern-like fruit. It forms a broad crown (to 15 m) with pinnate leaves that emerge hot-pink before turning green. Known as Luan in China, its flowers are used both as a yellow dye and in traditional medicine, and the tree is planted over the graves of scholars. The inflated capsular fruit are wind-blown, and they ultimately shatter in order to disseminate the seeds. Though it is naturalized in many places (Korea, Japan, and the U.S.), because of its drought tolerance and capacity for long-distance dispersal K. paniculata does not generally spread under Vancouver's wet winter conditions.

This specimen, planted at the Botanical Garden entrance, was grown from wild seed collected in South Korea. Another specimen from the same seed batch faced this tree from across the courtyard. The other tree was less compact in growth and considerably inferior with respect to flowering, but its seed capsules were always coloured bright red and very showy, whereas this specimen's fruits are always dull brown. Note the bald eagle perched on the Douglas fir snag in the distance.

Continuing with the small series on tropical fruits, today's image is thanks to aegisd@Flickr (original | BPotD Flickr Group Pool). It was very clever to place the rambutan on a platter with a clover illustration for a mirroring effect. Thank you!

Julia Morton's Fruits of Warm Climates once again provides one of the best online references: rambutan. Rambutan is native to Indonesia, though it has been subsequently introduced into cultivation throughout much of the tropics. Its family, the Sapindaceae, also includes the southern China natives lychee and longan.

Morton refers to a number of cultivars of rambutan; noting that this appears to have been cultivated in Thailand, I'm going to assume this fruit is from one of the cultivated varieties, but I'll have to leave it to others with more expertise to determine the name of the one in this photograph (if that's possible on fruit and origin alone).

For more photographs, I'll again suggest the USDA's Pacific Basin Tropical Plant Genetic Resources unit's images of its accessions: Nephelium. Wikipedia draws some of its information from Morton's work, though there are some particularly interesting additional tidbits regarding the reproduction of rambutan plants if you read the entire article: Nephelium lappaceum.