Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Five-point scale for evaluating flowering and autumn discolouration_
| Flowering | Autumn discolouration | |
|---|---|---|
| 4 | Flowers clearly visible, coverage >50%, colour different from green | Intense discolouration (red, orange, bright yellow) throughout the entire crown |
| 3 | Flowers clearly visible, coverage <50%, colour different from green | Discolouration of moderate or variable intensity (yellow, dull orange) throughout the entire crown |
| 2 | Flowers poorly visible, sparse, colour different from green | Uneven discolouration affecting 30%–80% of the crown volume |
| 1 | Flowers poorly visible or not noticeable, green | Only a few leaves changing colour (up to 30%), with low intensity |
| 0 | No flowering | No discolouration |
Three-point scale for evaluating ornamental features of maples_
| Fruits | Foliage texture | Leaves | Bark and/or shoots | Habit | Overall tree health | |
|---|---|---|---|---|---|---|
| 2 | Numerous colourful or otherwise distinctive fruits covering the entire crown | Even regular foliage pattern throughout the crown | Decorative, distinctive leaves | Shoots and/or bark with distinctive colouring or an interesting texture | A distinctive, regular habit (umbrella-shaped, ovoid, columnar, etc.) | No signs of disease or pests |
| 1 | Colourful or distinctive fruits scattered or only visible at close range | Regular foliage pattern visible only in parts of the crown | Partially interesting leaves | Moderately conspicuous shoots and/or bark | A moderately regular habit of limited ornamental value | Scattered or minor disease symptoms, or limited to part of the crown |
| 0 | No fruits or fruits not distinctive, blending into the background | Chaotic foliage arrangement, unclear foliage texture | Inconspicuous leaves | Indistinct shoots and/or bark | An irregular, asymmetrical habit | Widespread disease symptoms (e.g. discolouration, leaf deformation) across the entire crown |
Overview of growth performance and ornamental features of 33 Acer species_
| Species name | CSR (width/height) | Flowers (max = 4) | Fruits (max = 2) | Leaves (max = 2) | Bark/shoots (max = 2) | Foliage pattern (max = 2) | Habit (max = 2) | Health (max = 2) | Autumn discoloration (max = 4) | Standardised sum (SD) |
|---|---|---|---|---|---|---|---|---|---|---|
| Section Palmata | ||||||||||
| A. amoenum | 1.12 | 2.47 | 0.87 | 1.93 | 0.00 | 2.00 | 2.00 | 2.00 | 3.87 | 5.05 (0.47) |
| A. circinatum | 0.87 | 2.30 | 0.00 | 2.00 | 0.00 | 1.00 | 0.80 | 1.50 | 2.30 | –1.57 (0.87) |
| A. japonicum | 0.72 | 2.50 | 0.00 | 2.00 | 0.00 | 1.25 | 1.00 | 2.00 | 3.00 | 0.65 (0.63) |
| A. oliverianum | 0.69 | 2.00 | 0.00 | 2.00 | 0.00 | 1.00 | 1.00 | 1.63 | 1.38 | –2.33 (1.00) |
| A. palmatum | 0.58 | 2.00 | 0.00 | 2.00 | 0.00 | 2.00 | 2.00 | 2.00 | 3.10 | 2.32 (0.17) |
| A. pseudosieboldianum | 0.84 | 2.00 | 0.00 | 2.00 | 0.00 | 1.40 | 1.60 | 1.60 | 2.60 | 0.02 (0.68) |
| A. shirasawanum | 0.58 | 2.38 | 1.13 | 2.00 | 0.00 | 1.63 | 2.00 | 2.00 | 2.13 | 3.43 (0.88) |
| A. sieboldianum | 0.66 | 1.00 | 0.00 | 2.00 | 0.00 | 1.80 | 2.00 | 1.80 | 2.50 | 0.12 (0.39) |
| Section Macrantha | ||||||||||
| A. davidii | 0.70 | 2.25 | 0.25 | 2.00 | 1.13 | 2.00 | 1.50 | 1.75 | 2.13 | 2.76 (0.72) |
| A. pensylvanicum | 0.55 | 2.33 | 0.00 | 2.00 | 1.89 | 1.78 | 2.00 | 2.00 | 3.44 | 5.60 (0.49) |
| A. rufinerve | 0.55 | 2.00 | 0.50 | 2.00 | 1.63 | 1.75 | 1.88 | 2.00 | 2.88 | 5.01 (0.81) |
| A. tegmentosum | 0.60 | 1.30 | 0.00 | 1.70 | 1.80 | 1.20 | 1.30 | 1.40 | 3.70 | 1.66(1.39) |
| Section Platanoidea | ||||||||||
| A. cappadocicum | 0.55 | 2.11 | 0.00 | 0.44 | 0.00 | 0.67 | 0.78 | 2.00 | 1.56 | –4.26 (0.53) |
| A. divergens | 0.33 | 0.88 | 0.00 | 0.25 | 0.00 | 0.00 | 1.75 | 1.50 | 0.50 | –7.18 (0.68) |
| A. lobelii | 0.46 | 2.13 | 0.00 | 1.13 | 0.00 | 1.63 | 2.00 | 2.00 | 1.75 | –0.47 (0.75) |
| A. pictum | 0.60 | 2.12 | 0.06 | 1.53 | 0.00 | 1.00 | 1.65 | 1.65 | 1.88 | –1.40 (0.67) |
| Section Trifoliata | ||||||||||
| A. griseum | 0.69 | 2.58 | 0.50 | 1.00 | 2.00 | 1.17 | 1.58 | 1.67 | 2.50 | 2.90 (0.57) |
| A. mandshuricum | 0.56 | 2.13 | 0.50 | 2.00 | 0.00 | 2.00 | 1.63 | 2.00 | 3.50 | 3.27 (0.97) |
| A. maximowiczianum | 0.65 | 1.00 | 0.00 | 1.63 | 0.00 | 1.13 | 1.50 | 1.75 | 2.38 | –2.00 (0.97) |
| A. triflorum | 0.83 | 1.13 | 0.50 | 1.75 | 1.00 | 1.25 | 1.88 | 2.00 | 4.00 | 3.30 (0.94) |
| Section Arguta | ||||||||||
| A. argutum | 0.84 | 1.00 | 0.55 | 0.91 | 0.00 | 0.00 | 1.45 | 1.00 | 1.82 | –5.05 (0.54) |
| A. barbinerve | 0.86 | 1.00 | 0.00 | 0.90 | 0.10 | 0.20 | 1.20 | 1.20 | 1.50 | –5.99 (0.69) |
| A. stachyophyllum | 0.88 | 1.13 | 0.00 | 1.63 | 0.75 | 0.25 | 2.00 | 1.40 | 1.38 | –2.83 (1.13) |
| Section Cissifolia | ||||||||||
| A. cissifolium | 0.85 | 3.38 | 1.13 | 1.88 | 0.00 | 1.75 | 1.88 | 2.00 | 2.50 | 4.68 (0.93) |
| A. henryi | 1.07 | 2.56 | 0.67 | 2.00 | 0.00 | 0.89 | 2.00 | 1.44 | 1.56 | 0.54 (0.69) |
| Section Acer series Monspessulana | ||||||||||
| A. monspessulanum | 0.73 | 2.36 | 0.00 | 1.09 | 0.00 | 1.09 | 0.82 | 2.00 | 1.55 | –2.57 (0.99) |
| A. opalus | 0.62 | 2.36 | 0.00 | 0.55 | 0.00 | 1.09 | 1.09 | 1.82 | 2.00 | –2.83 (0.51) |
| Section Acer series Saccharodendron | ||||||||||
| A. saccharum | 0.46 | 3.00 | 0.00 | 2.00 | 0.00 | 1.60 | 2.00 | 2.00 | 2.80 | 2.68 (0.33) |
| Section Indivisa | ||||||||||
| A. carpinifolium | 0.94 | 2.30 | 0.00 | 2.00 | 0.00 | 2.00 | 2.00 | 2.00 | 3.30 | 2.84 (0.42) |
| Section Lithocarpa | ||||||||||
| A. tsinglingense | 0.65 | 0.88 | 0.00 | 0.38 | 0.00 | 0.75 | 0.25 | 2.00 | 3.63 | –4.31 (0.84) |
| Section Pentaphylla series Trifida | ||||||||||
| A. buergerianum | 0.62 | 1.13 | 0.00 | 1.63 | 0.00 | 0.75 | 0.75 | 1.50 | 1.63 | –4.37(1.07) |
| Section Rubra | ||||||||||
| A. rubrum | 0.38 | 2.79 | 0.57 | 1.00 | 0.00 | 0.86 | 1.71 | 1.57 | 3.29 | 0.68 (1.11) |
| Section Spicata | ||||||||||
| A. ukurunduense | 0.77 | 2.50 | 0.00 | 0.38 | 0.75 | 1.00 | 1.50 | 1.50 | 1.88 | –2.00 (1.02) |
Summary of average and maximum tree heights, along with the corresponding values reported in key dendrological literature sources: SEN—Seneta (1991); GEL—van Gelderen et al_ (1994)_
| Taxon name | Mean height | Maximum height | SEN | GEL |
|---|---|---|---|---|
| Section Palmata | ||||
| A. amoenum | 8.73 | 12 | 10 (15) | 10 |
| A. circinatum | 9.00 | 13 | 10 (12) | 10 |
| A. japonicum | 8.19 | 10.5 | 10 (15) | 8–10 |
| A. oliverianum | 9.63 | 12 | – | 8–10 |
| A. palmatum | 12.30 | 16.5 | 10 (15) | 10 |
| A. pseudosieboldianum | 7.75 | 12 | 8 | 8 |
| A. shirasawanum | 10.31 | 16 | 10 (15) | 7.5 (15) |
| A. sieboldianum | 11.00 | 12.5 | 10 (15) | 10 |
| Section Macrantha | ||||
| A. davidii | 10.31 | 17 | 15 | 10–15 |
| A. pensylvanicum | 12.72 | 18 | 12 | 10–12 |
| A. rufinerve | 7.88 | 9 | 15 (20) | 15 |
| A. tegmentosum | 9.55 | 14 | 15 | 10 |
| Section Platanoidea | ||||
| A. cappadocicum | 11.17 | 18 | 20 (25) | 25–30 |
| A. divergens | 6.19 | 10.5 | … | 10 |
| A. lobelii | 14.63 | 20.5 | 20 (30) | 20 |
| A. pictum | 12.06 | 22 | 15 (20) | 15 |
| Section Trifoliata | ||||
| A. griseum | 8.29 | 12.5 | 12 | 15 |
| A. mandshuricum | 9.56 | 13 | 10 (20) | 5–6 |
| A. maximowiczianum | 10.25 | 12.5 | 20 (25) | 15 |
| A. triflorum | 7.94 | 12 | 8 | 10 |
| Section Arguta | ||||
| A. argutum | 9.86 | 11.5 | 8 | 6 |
| A. barbinerve | 6.90 | 9.5 | 12 | 10 |
| A. stachyophyllum | 9.50 | 12.5 | 10 | … |
| Section Cissifolia | ||||
| A. cissifolium | 9.31 | 15 | 10 | 12 |
| A. henryi | 8.06 | 12 | 10 | 10 |
| Section Acer Series Monspessulana | ||||
| A. monspessulanum | 8.77 | 15 | 15 | 6–12 |
| A. opalus | 10.88 | 15 | 15 (20) | 10–13 |
| Section Acer Series Saccharodendron | ||||
| A. saccharum | 20.95 | 29 | 40 | 40 |
| Section Indivisa | ||||
| A. carpinifolium | 6.40 | 10 | 15 (20) | 10 |
| Section Lithocarpa | ||||
| A. tsinglingense | 7.88 | 10.5 | - | 15* |
| Section Pentaphylla Series Trifida | ||||
| A. buergerianum | 5.50 | 9.5 | 10 | 25 |
| Section Rubra | ||||
| A. rubrum | 20.79 | 30 | 40 | 20–40 |
| Section Spicata | ||||
| A. ukurunduense | 8.19 | 12.5 | 10 (14) | 7–10 |