Height: about 13 metres

Circumference: 77 cm + 42 cm (the trunk forks into two parts)

It has a bushy structure and grows very closely to a robinia tree (we can’t measure the trunk circumference).

Height: about 11 metres

We can see weather data on its website:

https://stazioni.meteoproject.it/dati/marcallo/

Sky is cloudy (broken), temperature at 11:15 a.m. is 18 degrees.

Biometry in a Karlovac alley. That alley is one part of the alley surrounding Karlovac star (Karlovac was created as a fortress in the shape of a six-pointed star)

circumference : 122 +135 (the trunk forks into two parts)

age of tree: 60 years

circumference: 135 cm

age of tree: 54 years

air temperature at 13.00 : 26C

clouds: 1- 10%

air temperature at 13.00 : 26C

clouds: 1- 10%

leaf 2: 5GY 3/2

leaf 3 and 4: 5GY 4/8

air temperature at 13.00: 20C

clouds: 25 - 50%

leaf 3 and 4: 5GY 4/8

air temperature at 13.00 : 20 C

clouds: 25 - 50%

air temperature : 20 C

clouds: 25 - 50%

The students measure water temperature, pH, disolved oxigen, nitrates and nitrites, alkalinity and water transparency.

3 rd class

leaf 2: 5GY 3/2

leaf 3 : 5GY 4/8

leaf 4: 5GY 4/8

leaf 2: 5GY 3/2

leaf 3: 5GY 4/8

leaf 4: 5GY 4/8

leaf 3 and 4: 5GY 4/8

air temperature at 13.00 : 23C

clouds: 25 - 50%

leaf 2: 5GY 3/2

leaf 3 and 4: 5GY 4/2

air temperature: 23 C

clouds: 25 - 50%

Air temperature at 3:00 pm is 21 degrees Celsius, the weather is sunny with isolated clouds.

Air temperature at 12:30 pm is 15 degrees Celsius, the sky is cloudy (overcast).

Air temperature at 3:00 pm is 21 degrees Celsius, the weather is sunny with isolated clouds.

Leaf 1: 5GY 3/2

Leaf 2: 5GY 3/2

Leaf 3: 5GY 3/2

Leaf 4: 5GY 4/8

Air temperature at 12:30 is 15 degrees Celsius, it’s cloudy (overcast).

Outdoor activities for GLOBE students in Karlovac.

leaf 2: 5GY 3/2

leaf 3 and 4: 5GY 4/2

leaf 2: 5GY 3/2

leaf 3: 5GY 4/8

leaf 4: 5GY 4/10

leaf 2: 5GY 3/2

leaf 3 and 4: 5GY 4/8

air temperature at 13.00: 20C

clouds: 50 - 90%

Air temperature at 13:00 is 17 degrees Celsius, the sky is cloudy (broken, 50%-90%) without precipitation.

Measuring trees’ height with paper clinometer…

leaf 2: 5GY 4/2

leaf 3: 5GY 4/8

leaf 4: 5GY 4/10

air temperature at 13.30: 20C

clouds: 1- 10%

leaf 2: 5GY 5/10

leaf 3: 5GY 4/8

leaf 4: 5GY 4/8

leaf 2: 5GY 3/2

leaf 3: 7,5YR 5/4

leaf 4: 7,5 YR 5/4

Leaf 1: 5GY 4/8

Leaf 2: 5GY 4/8

Leaf 3: 5GY 4/8

Leaf 4: 2.5Y 8/12

Temperature at 13:30: 21 degrees Celsius

Cloud cover: scattered (25%-50%)

Leaves on the same branch but nearer to the trunk appear lighter green than terminal ones.

All four leaves are still 5GY 3/2

Temperature:18.0 degrees

Humidity: 80%

12:45

Temperature : 15.4 degrees

Humidity : 78%

The Sky is cloudy

12:41

Temperature: 15.4 degrees

Humidity: 78%

The Sky is cloudy .

16:04

Temperature:18.5 degrees

Humidity: 76%

The Sky is cloudy

leaf 2: 5GY 4/2

leaf 3: 5GY 4/8

leaf 4: 5GY 5/10

air teperature at 13.00: 21 C

clouds: 50- 90%

leaf 2: 5GY 6/10

leaf 3: 5GY 7/12

leaf 4: 5GY 7/12

leaf 2: 7,5 YR 5/4

leaf 3: 7,5 YR 3/4

leaf 4: 7,5 YR 3/4

soil temperature at 5 cm: 18 C

leaf 2: 5GY 5/10

leaf 3: 5GY 5/10

leaf 4: 2,5Y 8/12

air temperature at 13.00: 15C

clouds: 1 - 10%

leaf 2: 5GY 6/10

leaf 3: 5GY 7/12

leaf 4: 2,5Y 8/12

leaf 2: 5GY 4/2

leaf 3: 5GY 3/2

leaf 4: 5GY 3/2

The other three leaves have slightly changed color tone:

Leaf n.1: 5GY 4/8

Leaf n.2: 5GY 5/10

Leaf n.3: 5GY 5/10

At 13:30 air temperature is 20.6 degrees Celsius

Cloud cover: scattered

The three leaves left on our branch are all more similar to 5GY 5/10.

All four leaves are still 5GY 3/2.

We suppose that it may depend on the shadow created by other nearby trees.

leaf 2: 5GY 5/10

leaf 3: 5GY 5/10

leaf 4: 5GY 8/12

leaf 2: 5GY 6/10

leaf 3: 5GY 7/12

leaf 4: 2,5Y 8/12

air temperature at 13.30: 9 C

clouds: 90 -100%

leaf 2: 5GY 5/10

leaf 3: 2,5Y 8/12

leaf 4: 2,5Y 8/12

air temperature at 13.00: 9C

clouds: 50-90%

leaf 2: 5GY 7/12

leaf 3: 2,5Y 8/12

leaf 4: 2,5Y 8/12

leaf 2: 5GY 4/2

leaf 3. 5GY 4/2

leaf 4.: 7,5YR 3/4

leaf 2: FALLEN

leaf 3: 2,5 Y 8/12

leaf 4: 2,5 YR 8/12

air temperature at 13.00: 15,5C

clouds: 10-25%

leaf 2: 5GY 7/12

leaf 3: 2,5Y 8/12

leaf 4: FALLEN

Leaf n.1-2-3: 5GY 7/12

Leaf n.4: fallen

At noon air temperature is 11 degrees Celsius, it’s sunny with transparent cirrostratus clouds.

Leaf n.1: 2.5Y 8/12

Leaf n.2: 2.5Y 8/12

Leaf n.3: 2.5Y 8/6

Leaf n.4: fallen

Today it’s cloudy and rather cold (air temperature at 12:30 is 7 degrees Celsius), the sky is overcast with low clouds, without precipitation.

Leaf n.1: fallen

Leaf n.2: 5YR 7/12

Leaf n.3: 5YR 7/12

Leaf n.4: fallen

Air temperature at 1:30 pm is 8 degrees Celsius, low clouds are covering the whole sky and there’s low visibility.

Leaf n.1-2-3: 5GY 5/10

Leaf n.4: 5GY 4/8

Sky has been very cloudy in Autumn time and we often had low visibility…

But leaves are still on hazel tree!

Leaf n.1:7.5YR 3/4 (it's completely dry and just after our observation it has fallen down)

Leaf n.2: fallen

Leaf n.3: 7.5YR 6/4

Leaf n.4: 7.5YR 6/4

current air temperature: 6C

clouds: 50 - 90 %

Today it's sunny, with cloud cover 25-50% (scattered). Air temperature at 13:30 is 10°C.

We selected 4 buds on the same branch we observed during Autumn Phenology Campaign.

All four buds are almost ready to swell!

At 12:00 air temperature is 5 °C, humidity 61% and cloud cover 100% (overcast).

At 12:00 air temperature is 14°C and humidity 54%; a light wind is blowing.

All four buds are dormant.

We've selected buds on the same branch that we observed in 2024 Autumn green down.

At 12:00 temperature is 14 degrees Celsius, humidity 61%; pressure 1016 hPa.

We’ve observed budburst on bud n.4; the other there buds are swelling.

Budburst : March 3rd

Budbust: March 3rd

Lenght measurement on March 17th, 2025:

Leaf 1: 19 mm

Leaf 2: 16 mm

Leaf 3: 14 mm

Leaf 4: 12 mm

We can measure only leaf. n.1 (10 mm); the other three buds are still swelling.

Our observed branch is awakening slowly, instead..

Leaf n.1: 34 mm

Leaf n.2: 34 mm

Leaf n.3: 31 mm

Leaf n.4: 25 mm

71% humidity

81% humidity

93%humidity

43% humidity

66z humidity

36% humidity

58% humidity

74% humidity

81% humidity

87 % humidity

66% humidity

93% humidity

36% humidity

58% humidity

93% humidity

43% humidity

We were waiting for them impatiently!

Leaf n.1: 16 mm

Leaf n.2: budburst

Leaf n.3: 9 mm

Leaf n.4: 35 mm

At 1:00 p.m. air temperature is 18°C, humidity 53%, moderate wind is blowing.

The sky is broken (50-90%), with cirrostratus clouds.

Leaf n.1: 57 mm

Leaf n.2: 45 mm

Leaf n.3: 46 mm

Leaf n.4: 63 mm

Leaf n.2: 17 mm

Leaf n.3: lost

Leaf n.4: 55 mm

Leaf n.2: 55 mm

Leaf n.3: 50 mm

Leaf n.4: 87 mm

Hazel leaves are growing fast:

Leaf n.1: 86 mm

Leaf n.2: 58 mm

Leaf n.3: 50 mm

Leaf n.4: 95 mm

Leaf n.2-3 seem to have slowed down their growth: they are hidden from other larger leaves and one of them appears without its tip (maybe eaten by any insect...)

Leaf n.2: 23 mm

Leaf n.3: lost

Leaf n.4: 61 mm

At 12:00 air temperature is 13°C, humidity 89%.

Leaf n.2: lost

Leaf n.3: lost

Leaf n.4: 63 mm

We've not been lucky in choosing the branch for green up observations: two leaves got lost, and the nearby branches have longer leaves. We've chosen the same barnch we observed in green down observations last Autumn.

Today, at 13:00, air temperature is 23°C, humidity 59%, high pressure and light wind from south. No clouds in the sky

Leaf n.2: 58 mm

Leaf n.3: 50 mm

Leaf n.4: 98 mm

Leaves n.1-2-3 have stopped growing. Leaves n.2-3 are shorter, because they are shaded by the nearby other ones.

Leaf n.2: lost

Leaf n.3: lost

Leaf n.4: 64 mm

Our birch has slow down its growth.

Last days we had bad weather, with frequent showers and thunderstorms; today the weather is getting better.

Leaf n.2: 57 mm

Leaf n.3: 50 mm

Leaf n.4: 97 mm

Leaf n.2: lost

Leaf n.3: lost

Leaf n.4: 65 mm

Leaves have just stopped growing; let’s see the final growing chart!

Our birch is full of leaves!

Leaf n.1: 88 mm

Leaf n.2: 57 mm

Leaf n.3: 50 mm

Leaf n.4: 97 mm

Cloud cover: broken, mainly high cirrustratus clouds

April 15th - full bloom

current air temperature; 22 C

3.th online meeting

Christmas customs in Croatia and Italy